Showing papers on "Debye model published in 2017"
TL;DR: Due to their ultra low lattice thermal conductivities coupled with high carrier mobilities, monolayer SnX2 materials may be promising materials for thermoelectric applications.
Abstract: Using density functional theory, we systematically investigate the lattice thermal conductivity and carrier mobility of monolayer SnX2 (X = S, Se). The room-temperature ultra low lattice thermal conductivities found in monolayer SnS2 (6.41 W m-1 K-1) and SnSe2 (3.82 W m-1 K-1) are attributed to the low phonon velocity, low Debye temperature, weak bonding interactions, and strong anharmonicity in monolayer SnX2. The predicted values of lattice thermal conductivity are lower than those of other two-dimensional materials such as stanene, phosphorene, monolayer MoS2, and bulk SnX2. High phonon-limited carrier mobilities are obtained for the monolayer SnX2. For example, the electron mobility of monolayer SnS2 is 756.60 cm2 V-1 s-1 and the hole mobility is 187.44 cm2 V-1 s-1. The electron mobility of these monolayers is higher than their hole mobility due to the low effective mass of electrons and low deformation constants, which makes them n-type materials. Due to their ultra low lattice thermal conductivities coupled with high carrier mobilities, monolayer SnX2 materials may be promising materials for thermoelectric applications.
159 citations
TL;DR: It is reported for the first time that a buckled structure has three conflicting effects: increasing the Debye temperature by increasing the overlap of the pz orbitals, suppressing the acoustic-optical scattering by forming an acoustic- optical gap, and increasing the flexural phonon scattering.
Abstract: Controlling heat transport through material design is one important step toward thermal management in 2D materials. To control heat transport, a comprehensive understanding of how structure influences heat transport is required. It has been argued that a buckled structure is able to suppress heat transport by increasing the flexural phonon scattering. Using a first principles approach, we calculate the lattice thermal conductivity of 2D mono-elemental materials with a buckled structure. Somewhat counterintuitively, we find that although 2D group-V materials have a larger mass and higher buckling height than their group-IV counterparts, the calculated κ of blue phosphorene (106.6 W mK−1) is nearly four times higher than that of silicene (28.3 W mK−1), while arsenene (37.8 W mK−1) is more than fifteen times higher than germanene (2.4 W mK−1). We report for the first time that a buckled structure has three conflicting effects: (i) increasing the Debye temperature by increasing the overlap of the pz orbitals, (ii) suppressing the acoustic–optical scattering by forming an acoustic–optical gap, and (iii) increasing the flexural phonon scattering. The former two, corresponding to the harmonic phonon part, tend to enhance κ, while the last one, corresponding to the anharmonic part, suppresses it. This relationship between the buckled structure and phonon behaviour provides insight into how to control heat transport in 2D materials.
132 citations
TL;DR: In this paper, the elastic behavior and thermodynamic properties of recently synthesized (Zr3−xTix)AlC2 MAX phases are investigated for the first time using density functional theory and the quasi-harmonic model.
110 citations
TL;DR: In this article, the authors established a methodology to determine the Debye temperature, Gruneisen parameter, and lattice thermal conductivity using computationally feasible elastic properties (the bulk and shear moduli).
Abstract: Lattice thermal conductivity is one of the most important thermoelectric parameters in determining the energy conversion efficiency of thermoelectric materials. However, the lattice thermal conductivity evaluation requires time-consuming first-principles (quasi)phonon calculations, which limits seeking high-performance thermoelectric materials through high-throughput computations. Here, we establish a methodology to determine the Debye temperature $\mathrm{\ensuremath{\Theta}}$, Gr\"uneisen parameter $\ensuremath{\gamma}$, and lattice thermal conductivity $\ensuremath{\kappa}$ using computationally feasible elastic properties (the bulk and shear moduli). For 39 compounds with three different prototypes (the cubic isotropic rocksalt and zinc blende, and the noncubic anisotropic wurtzite), the theoretically calculated $\mathrm{\ensuremath{\Theta}},\ensuremath{\gamma}$, and $\ensuremath{\kappa}$ are in reasonable agreement with those determined using (quasi)harmonic phonon calculations or experimental measurements. Our results show that the methodology is an efficient tool to predict the anharmonicity and the lattice thermal conductivity.
100 citations
TL;DR: The results reveal that FeCrRuSi is a half-metallic material (HMM) with a total magnetic moment of 2.0 μB in agreement with the well-known Slater-Pauling rule and is found to exist in an EQH type structure with the presence of some B2 disorder.
Abstract: In this paper, we have investigated the structural, electronic, magnetic, half-metallic, mechanical, and thermodynamic properties of the equiatomic quaternary Heusler (EQH) compound FeCrRuSi using the density functional theory (DFT) and the quasi-harmonic Debye model. Our results reveal that FeCrRuSi is a half-metallic material (HMM) with a total magnetic moment of 2.0 μB in agreement with the well-known Slater-Pauling rule Mt = Zt − 24. Furthermore, the origin of the half-metallic band gap in FeCrRuSi is well studied through a schematic diagram of the possible d-d hybridization between Fe, Cr and Ru elements. The half-metallic behavior of FeCrRuSi can be maintained in a relatively wide range of variations of the lattice constant (5.5–5.8 A) under uniform strain and the c/a ratio (0.96–1.05) under tetragonal distortion. The calculated phonon dispersion, cohesive and formation energies, and mechanical properties reveal that FeCrRuSi is stable with an EQH structure. Importantly, the compound of interest has been prepared and is found to exist in an EQH type structure with the presence of some B2 disorder. Moreover, the thermodynamic properties, such as the thermal expansion coefficient α, the heat capacity CV, the Gruneisen constant γ, and the Debye temperature ΘD are calculated.
76 citations
TL;DR: In this article, the synthesis temperature and Eu2+-doping content induced phase selection and variations of the local structures in nepheline, low-carnegieite and high carnegieite types of NaAlSiO4 polymorphs were studied in detail.
Abstract: The union of temperature-dependent phase transition and relating structural transformation via modification of chemical compositions is of fundamental importance for the discovery of new materials or their functional properties optimization. Herein, the synthesis temperature and Eu2+-doping content induced phase selection and variations of the local structures in nepheline, low-carnegieite and high-carnegieite types of NaAlSiO4 polymorphs were studied in detail. The luminescence of Eu2+ in low-carnegieite and nepheline phases shows blue (460 nm) and yellow (540 nm) broad-band emissions, respectively, under near-ultraviolet excitation. The photoluminescence evolution can be triggered by the different synthesis temperatures in relation to the Eu2+-doping concentration, as corroborated by density functional theory calculations on the local coordination structures and corresponding mechanical stabilities in terms of the Debye temperature. The fabricated white light-emitting diode device with high color render...
75 citations
TL;DR: In this paper, temperature-dependent thermal conductivity in the range between 7 and 300 K was measured for CH3NH3PbI3 and compared to a Debye model via the Callaway method, and it was shown that a resonant phonon scattering term can account for the difference in thermal transport behavior between the perovskite with a methylammonium ion versus a single cesium atom in the cationic A site of the lattice.
Abstract: Temperature-dependent thermal conductivity in the range between 7 and 300 K was measured for CH3NH3PbI3 and CsPbI3 and compared to a Debye model via the Callaway method. Thermal conductivity was found to be extremely low across the whole temperature range for both materials, with CH3NH3PbI3 lower than CsPbI3. Fitting analysis showed that a resonant phonon scattering term can account for the difference in thermal transport behavior between the perovskite with a methylammonium (MA) ion versus a single cesium atom in the cationic A site of the lattice. The resonant frequency associated with this term is in the range of ∼15–30 cm–1, pointing to the rotational degree of freedom of the organic ion. Analysis of the temperature dependence of the possible phonon scattering mechanisms showed that thermal conductivity of both CH3NH3PbI3 and CsPbI3 perovskites was dominated by Umklapp scattering at room temperature, and the rotation of the organic cation may be responsible for suppressing the thermal conductivity of ...
70 citations
TL;DR: In this article, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe 3 Al, FeAl, Fe Al 2, Fe 2 Al 5 and FeAl 3 ) binary compounds were calculated.
Abstract: Using the first-principles calculations, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe 3 Al, FeAl, FeAl 2 , Fe 2 Al 5 and FeAl 3 ) binary compounds were calculated. The formation enthalpy and cohesive energy of these Fe-Al compounds are negative, and show they are thermodynamically stable structures. Fe 2 Al 5 has the lowest formation enthalpy, which shows the Fe 2 Al 5 is the most stable of Fe-Al binary compounds. These Fe-Al compounds display disparate anisotropy due to the calculated different shape of the 3D curved surface of the Young’s modulus and anisotropic index. Fe 3 Al has the biggest bulk modulus with the value 233.2 GPa. FeAl has the biggest Yong’s modulus and shear modulus with the value 296.2 GPa and 119.8 GPa, respectively. The partial density of states, total density of states and electron density distribution maps of the binary Fe-Al binary compounds are analyzed. The bonding characteristics of these Fe-Al binary compounds are mainly combination by covalent bond and metallic bonds. Meanwhile, also exist anti-bond effect. Moreover, the Debye temperatures and sound velocity of these Fe-Al compounds are explored.
69 citations
TL;DR: In this article, the composition dependent elastic and thermal properties of Li Zn ferrite (Li0.5-x/2ZnxFe2.0) ceramics were reported.
66 citations
TL;DR: In this article, the authors employed non-equilibrium molecular dynamics simulations to examine the applicability of four kinds of interatomic potential models: the Tersoff, the REBO, the opt-Tersoff and the AIREBO, which are widely used to model the thermal transport in single and multi-layer graphene, as well as graphite crystallites.
65 citations
TL;DR: In this article, the effect of transition metals (TM=Mo and Re) on the strength and high-temperature thermodynamic properties of NbSi2 with C40 structure was investigated.
TL;DR: Attempts at fitting the experimental spectrum using the gLST relation as a constraint indicate that the traditional way of fitting the excess response with secondary and tertiary Debye relaxations is problematic.
Abstract: We critically review the literature on the Debye absorption peak of liquid water and the excess response found on the high frequency side of the Debye peak. We find a lack of agreement on the microscopic phenomena underlying both of these features. To better understand the molecular origin of Debye peak we ran large scale molecular dynamics simulations and performed several different distance-dependent decompositions of the low frequency dielectric spectra, finding that it involves processes that take place on scales of 1.5-2.0 nm. We also calculated the k-dependence of the Debye relaxation, finding it to be highly dispersive. These findings are inconsistent with models that relate Debye relaxation to local processes such as the rotation/translation of molecules after H-bond breaking. We introduce the spectrumfitter Python package for fitting dielectric spectra and analyze different ways of fitting the high frequency excess, such as including one or two additional Debye peaks. We propose using the generalized Lydanne-Sachs-Teller (gLST) equation as a way of testing the physicality of model dielectric functions. Our attempts at fitting the experimental spectrum using the gLST relation as a constraint indicate that the traditional way of fitting the excess response with secondary and tertiary Debye relaxations is problematic. All of our work is consistent with the recent theory of Popov et al. (2016) that Debye relaxation is due to the migration of Bjerrum-like defects in the hydrogen bond network. Under this theory, the mechanism of Debye relaxation in liquid water is similar to the mechanism in ice, but the heterogeneity and power-law dynamics of the H-bond network in water results in excess response on the high frequency side of the peak.
TL;DR: In this paper, the semiconducting polycrystalline ferrite materials with the general formula Ni1−x¯¯¯¯ Mg====== x¯¯¯¯ Fe2O4 were synthesized by using the solid state reaction method.
Abstract: The semiconducting polycrystalline ferrite materials with the general formula Ni1−x
Mg
x
Fe2O4 were synthesized by using the solid state reaction method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrographs, and atomic force microscopy techniques were utilized to study the structural parameters. XRD confirms the formation of single phase cubic spinel structure of the ferrites. The crystallite sizes of ferrites determined using the Debye–Scherer formula ranges from 0.963 μm to 1.069 μm. The cation distribution of ferrite shows that Mg2+ ions occupy a tetrahedral site (A-site) and the Ni2+ ion occupy an octahedral site (B-site) whereas Fe3+ ions occupies an octahedral as well as a tetrahedral site. The study of elastic parameters such as the longitudinal modulus, rigidity modulus, Young’s modulus, bulk modulus, and Debye temperature were estimated using the FTIR technique. The decrease of direct current (DC) resistivity with increase in temperature indicates the semiconducting nature of ferrites. The dielectric constant as well as loss tangent decreases with increase in frequency, and at still higher frequencies, they are almost constant. This shows usual dielectric dispersion behavior attributed to the Maxwell–Wagner type of interfacial polarization and is in accordance with Koop’s phenomenological theory. The linear increase of alternating current conductivity with increase of frequency shows the small polaron hopping type of conduction mechanism in all the ferrites. The magnetic properties such as saturation magnetization (M
s
), magnetic moment, coercivity, remnant magnetization (M
r
), and the ratio of M
r
/M
s
was estimated using the M–H loop.
TL;DR: In this paper, the structural, electronic, magnetic and elastic properties of BaNpO 3 oxide are reported using full potential augmented plane wave method, where the optimized lattice parameters, the local density approximation (LDA) and generalized gradient approximation (GGA) have been used.
TL;DR: In this article, the elastic and thermal properties of single-phase ternary and quaternary Al-Ti-V-Cr-Nb-Mo refractory high-entropy alloys based on the first-principles calculations are studied.
TL;DR: In this paper, a series of as-synthesized Co 1−x Sr x Fe 2 O 4 nano-ferrites, 0.0 − 0.6, were prepared by the chemical co-precipitation method.
TL;DR: In this article, a detailed theoretical solid-state density functional theory study of γ-UO3 was carried out, where lattice parameters, bond lengths, bond angles, and X-ray powder pattern were found in very good agreement with their experimental counterparts determined by Xray diffraction.
Abstract: Gamma uranium trioxide, γ-UO3, is one of the most important polymorphs in uranium trioxide system, which is common throughout the nuclear fuel cycle and used industrially in the reprocessing of nuclear fuel and uranium enrichment. In this work, a detailed theoretical solid-state density functional theory study of this material was carried out. The computed lattice parameters, bond lengths, bond angles, and X-ray powder pattern were found in very good agreement with their experimental counterparts determined by X-ray diffraction. The equation of state of γ-UO3 was obtained, and therefore, the values of the bulk modulus and its derivatives, for which there are not experimental data to compare with, were predicted. The computed bulk modulus differs from that of a previous density functional theory calculation by only 4.4%. The thermodynamic properties of this material, including heat capacity, entropy, enthalpy, free energy, and Debye temperature were also determined as a function of temperature in the range...
TL;DR: In this article, the elastic properties, Debye temperature, Mulliken population, Vickers hardness, and charge density of two recently synthesized superconducting ScRhP and ScIrP pnictides are investigated.
Abstract: For the first time, we have reported in this study an ab initio investigation on elastic properties, Debye temperature, Mulliken population, Vickers hardness, and charge density of the two recently synthesized superconducting ScRhP and ScIrP pnictides The optimized cell parameters show fair agreement with the experimental results The mechanical stability of both ternary phosphides is confirmed via the calculated elastic constants Both compounds are ductile in nature and damage tolerant ScIrP is expected to be elastically more anisotropic than ScRhP The estimated value of Debye temperature predicts that ScRhP is thermally more conductive than ScIrP and the phonon frequency in ScRhP is higher than that in ScIrP Both pnictides are soft and easily machinable due to their low Vickers hardness Moreover, the hardness of ScRhP is lower due to the presence of antibonding Rh-Rh in ScRhP The metallic conductivity of ScRhP reduces significantly when Rh is replaced with Ir The main contribution to the total density of states (TDOS) at Fermi-level (EF) comes from d-electrons of Sc and Rh/Ir in both pnictides These two ternary compounds are characterized mainly by metallic and covalent bonding with little ionic contribution The calculated superconducting transition temperatures fairly coincide with the reported measured values
TL;DR: In this article, a double perovskite superconductor (K1.00), Ba1.3(Bi0.89Na0.11)4O12 with a Tc ∼ 31.5 k has been synthesized via the hydrothermal route.
TL;DR: In this article, the broadening of the absorption edge in a single crystal cubic zirconia below the conduction band was measured, suggesting the generation of energy levels that are consistent with the electroluminescent spectra.
Abstract: We report two measurements related to flash experiments. One is concerned with electroluminescence in yttria-stabilized zirconia; in this case we have measured the broadening of the (UV) absorption edge in single crystal cubic zirconia below the conduction band, suggesting the generation of energy levels that are consistent with the electroluminescent spectra. The second measurement relates to the universal nature of the power density at the early onset of the flash transition in Stage I, for several ceramics flashed under a wide range of electric fields and temperature, which may be related to nonlinear thermal vibrations, so that the Debye temperature would be a lower bound for the flash-onset.
TL;DR: In this article, the thermodynamic and mechanical properties of rutherfordine, a uranyl carbonate mineral, were studied by means of first principles calculations based on density functional theory.
Abstract: The thermodynamic and mechanical properties of rutherfordine, a uranyl carbonate mineral, were studied by means of first principles calculations based on density functional theory. Thermodynamic properties, including enthalpy, free energy, entropy, heat capacity, and Debye temperature, were evaluated as a function of temperature and compared with experimental data in the 300–700 K range. Our calculations show very good agreement with experimental data, and based on them, the knowledge of these properties is extended to the temperature range from 0 to 1000 K, including the full range of thermal stability (0–700 K). The computed values of the heat capacity, entropy, and free energy at 298 K deviate from the experimental values by about 8, 0.3, and 0.3%, respectively. At 700 K, the corresponding differences remain very small, 3.9, 2.3, and 1.3%, respectively. The equation of state and mechanical properties were also computed. The crystalline structure is seen to be mechanically and dynamically stable. Ruther...
TL;DR: In this paper, the effects of Li concentration on the Mg-Li binary system were investigated, and five ground state structures were found at Li 1 Mg13, Li 2 Mg2, Li 3 Mg1, Li 7 Mg 2 and Li 15 Mg 1 compositions, and the effect of the phonon band gap on lattice thermal conductivity was investigated.
TL;DR: In this paper, the effect of pressure on structural and mechanical properties as well as the temperature dependence of thermodynamic properties, such as enthalpies of formation, elastic moduli, anisotropy, heat capacity and thermal expansion coefficient of Ni 2 XAl (X = Sc, Ti, V) Heusler compounds are investigated implementing first-principles calculations.
TL;DR: In this paper, the average electron-phonon coupling of Bi$_2$Te$_3$(111) was determined by adapting a recently developed quantum-theoretical derivation of the helium scattering probabilities to the case of degenerate semiconductors.
Abstract: We have studied the topological insulator Bi$_2$Te$_3$(111) by means of helium atom scattering. The average electron-phonon coupling $\lambda$ of Bi$_2$Te$_3$(111) is determined by adapting a recently developed quantum-theoretical derivation of the helium scattering probabilities to the case of degenerate semiconductors. Based on the Debye-Waller attenuation of the elastic diffraction peaks of Bi$_2$Te$_3$(111), measured at surface temperatures between $110~\mbox{K}$ and $355~\mbox{K}$, we find $\lambda$ to be in the range of $0.04-0.11$. This method allows to extract a correctly averaged $\lambda$ and to address the discrepancy between previous studies. The relatively modest value of $\lambda$ is not surprising even though some individual phonons may provide a larger electron-phonon interaction.
Furthermore, the surface Debye temperature of Bi$_2$Te$_3$(111) is determined as ${\rm \Theta}_D = (81\pm6)~\mbox{K}$. The electronic surface corrugation was analysed based on close-coupling calculations. By using a corrugated Morse potential a peak-to-peak corrugation of 9% of the lattice constant is obtained.
TL;DR: In this paper, a combinatorial approach is presented to elucidate which definitions of both variables produce the best predictions of the lattice thermal conductivity, κ l. A set of 42 compounds was used to test the accuracy and robustness of all possible combinations.
TL;DR: In this article, first principles pseudopotential calculations have been performed for the first time to investigate the phonon dispersion, thermodynamic and optical properties including charge density, Fermi surface, Mulliken population analysis, theoretical Vicker hardness of predicted MAX phase Sc2InC.
Abstract: First principles pseudopotential calculations have been performed for the first time to investigate the phonon dispersion, thermodynamic and optical properties including charge density, Fermi surface, Mulliken population analysis, theoretical Vickers hardness of predicted MAX phase Sc2InC We revisited the structural, elastic and electronic properties of the compound which assessed the reliability of our calculations The analysis of the elastic constants and the phonon dispersion along with phonon density of states indicates the mechanical stability and dynamical stability of the MAX phase The Helmholtz free energy, internal energy, entropy specific heat capacity and Debye temperature have also been calculated from the phonon density of states Mulliken population analysis indicates the existence of prominent covalency in chemical bonding of Sc2InC The electronic charge density mapping shows a combination of ionic, covalent and metallic bonding in the compound The Fermi surface is comprised due to the low dispersive Sc 3d and C 2p states from the [ScC] blocks The phase is expected to be a soft material and easily mechinable due to its low Vicker hardness value Furthermore, the analysis of various optical properties (such as dielectric function, refractive index, photoconductivity, absorption coefficients, loss function and reflectivity) suggests that the nanolaminate Sc2InC is a promising candidate for optoelectronic devices in the visible and ultraviolet energy regions and as a coating material to avoid solar heating
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TL;DR: In this paper, the authors employed density functional theory calculations to investigate the mechanical behavior, bonding nature and defect processes of the new ordered MAX phase Mo2ScAlC2, and verified the mechanical stability of the compound with its single crystal elastic constants.
Abstract: In the present study we employed density functional theory calculations to investigate the mechanical behavior, bonding nature and defect processes of the new ordered MAX phase Mo2ScAlC2. The mechanical stability of the compound is verified with its single crystal elastic constants. The new phase Mo2ScAlC2 is anticipated to be prone to shear along the crystallographic b and c axes, when a rational force is applied to the crystallographic a axis. The compressibility along the direction under uniaxial stress is expected to be easier in Mo2ScAlC2. Additionally, the volume deformation should be easier in Mo2ScAlC2 than in the isostructural Mo2TiAlC2. Mo2ScAlC2 is predicted to behave in a brittle manner. Due to its higher Debye temperature, Mo2ScAlC2 is expected to be thermally more conductive than Mo2TiAlC2. The cross-slip pinning procedure should be significantly easier in Mo2ScAlC2 as compared to Mo2TiAlC2. The new ordered MAX phase Mo2ScAlC2 has a mixed character of strong covalent and metallic bonding with limited ionic nature. Both Mo-C and Mo-Al bonds are expected to be more covalent in Mo2ScAlC2 than those of Mo2TiAlC2. the level of covalency of Sc-C bond is somewhat low compared to a similar bond Ti-C in Mo2TiAlC2. Due to its reduced hardness, Mo2ScAlC2 should be softer and more easily machinable compared to Mo2TiAlC2. Fermi surface topology of the new compound is formed mainly due to the low-dispersive Mo 4d-like bands. The intrinsic defect processes reveal that the level of radiation tolerance in Mo2ScAlC2 is not as high as in other MAX phases such as Ti3AlC2.
TL;DR: For the first time, the americium-based perovskite SrAmO3 has been studied with respect to its structural, electronic, magnetic, mechanical, and thermodynamic properties as discussed by the authors.
Abstract: For the first time, the americium-based perovskite SrAmO3 has been studied with respect to its structural, electronic, magnetic, mechanical, and thermodynamic properties The study has been carried within the well-known density functional theory (DFT) using different approximations such as local spin density approximation (LSDA), generalized gradient approximation (GGA), LSDA + U, GGA + U In order to check for the stable ground state, optimization was performed for non-magnetic, ferromagnetic, and anti-ferromagnetic phases, and the compound was found to be stable in the ferromagnetic phase The spin magnetic moment was obtained with different exchange correlations and was found to be an integer which is one of the consequences of half-metallic nature The half-metallic nature of SrAmO3 was also confirmed from spin-polarised band structure calculations using GGA, GGA + U, and mBJ, showing metallic nature in spin-up states and semi-conducting in spin-down states The elastic constants, Young modulus, shear modulus, Poisson ratio, and anisotropic factor were also calculated SrAmO3 was found to establish ductile and anisotropic nature Debye temperature was predicted to be 353 K from elastic constants The thermodynamic properties, like variation of specific heat capacity, thermal expansion, and entropy, were studied in the temperature range of 0 to 600 K
TL;DR: In this paper, the structural, electronic, optical and thermodynamic properties of Mo2Ga2C were investigated using density functional theory (DFT) within the generalized gradient approximation (GGA).
Abstract: The structural, electronic, optical and thermodynamic properties of Mo2Ga2C are investigated using density functional theory (DFT) within the generalized gradient approximation (GGA). The optimized crystal structure is obtained and the lattice parameters are compared with available experimental data. The electronic density of states (DOS) is calculated and analyzed. The metallic behavior for the compound is confirmed and the value of DOS at Fermi level is 4.2 states per unit cell per eV. Technologically important optical parameters (e.g., dielectric function, refractive index, absorption coefficient, photo conductivity, reflectivity, and loss function) are calculated for the first time. The study of dielectric constant (ɛ 1) indicates the Drude-like behavior. The absorption and conductivity spectra suggest that the compound is metallic. The reflectance spectrum shows that this compound has the potential to be used as a solar reflector. The thermodynamic properties such as the temperature and pressure dependent bulk modulus, Debye temperature, specific heats, and thermal expansion coefficient of Mo2Ga2C MAX phase are derived from the quasi-harmonic Debye model with phononic effect also for the first time. Analysis of T c expression using available parameter values (DOS, Debye temperature, atomic mass, etc.) suggests that the compound is less likely to be superconductor.
TL;DR: As-synthesized Fe2+CrxFe(2−x)O4 nanoferrites were prepared by the wet-chemical co-precipitation route and characterized by the X-ray diffraction, Brunauer-Emmett-Teller and transmission electron microscopy, IR spectra, thermographometry and vibrating sample magnetometry (VSM) techniques as discussed by the authors.