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Journal ArticleDOI: 10.1088/0256-307X/38/3/037401

Superconductivity and Charge Density Wave in Iodine-Doped CuIr$_{2}$Te$_{4}$

02 Mar 2021-Chinese Physics Letters (Chinese Physical Society)-Vol. 38, Iss: 3, pp 037401
Abstract: We report a systematic investigation on the evolution of the structural and physical properties, including the charge density wave (CDW) and superconductivity of the polycrystalline CuIr2Te4−x I x for 0.0 ≤ x ≤ 1.0. X-ray diffraction results indicate that both of a and c lattice parameters increase linearly when 0.0 ≤ x ≤ 1.0. The resistivity measurements indicate that the CDW is destabilized with slight x but reappears at x ≥ 0.9 with very high T CDW. Meanwhile, the superconducting transition temperature T c enhances as x increases and reaches a maximum value of around 2.95 K for the optimal composition CuIr2Te1.9I0.1 followed by a slight decrease with higher iodine doping content. The specific heat jump (ΔC/γT c) for the optimal composition CuIr2Te3.9I0.1 is approximately 1.46, which is close to the Bardeen–Cooper–Schrieffer value of 1.43, indicating that it is a bulk superconductor. The results of thermodynamic heat capacity measurements under different magnetic fields [C p(T, H)], magnetization M(T, H) and magneto-transport ρ(T, H) measurements further suggest that CuIr2Te4−x I x bulks are type-II superconductors. Finally, an electronic phase diagram for this CuIr2Te4−x I x system has been constructed. The present study provides a suitable material platform for further investigation of the interplay of the CDW and superconductivity.

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Topics: Charge density wave (55%)

6 results found

Open accessJournal Article
Abstract: Unconventional superconductivity often appears in proximity of symmetry-breaking electronic and magnetic orders. The relevance of spatiotemporal fluctuations of these orders for the superconducting pairing remains an open question. Here, nanoscale broken-symmetry states are probed by high-energy x-rays in a layered iridium ditelluride superconductor, where superconductivity emerges from an ordered dimer state. The study finds no fingerprints of dimer fluctuations in the superconducting compositional regime, yet provides evidence for the coexistence of superconductivity and nanoscale dimerization close to the phase boundary of these two electronic states.

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Topics: Superconductivity (53%)

5 Citations

Journal ArticleDOI: 10.1016/J.JALLCOM.2021.160981
Lingyong Zeng1, Dong Yan1, Yiyi He1, Mebrouka Boubeche1  +3 moreInstitutions (1)
Abstract: Here we report a detailed investigation on the structural and superconducting properties of previously unreported CuIr2-xTixTe4 (0 ≤ x ≤ 0.2) samples. It is found that the charge density wave-like order is quickly suppressed with subtle Ti substitution on 5d Ir site in CuIr2Te4 and vanishes in all Ti-doped samples. Concurrently, superconducting critical temperature Tc is enhanced and increases up to 2.84 K at x = 0.075; thenceforth, Tc deceases with higher Ti-doped concentrations and forms a weak dome-shaped superconducting phase diagram. The optimal CuIr1.925Ti0.075Te4 composition exhibits type-Ⅱ superconductivity with its lower critical field (Hc1(0)) and upper critical field (Hc2(0)) based on Werthamer Helfand Hohenburg (WHH) model is 0.095 T and 0.212 T, respectively. The normalized specific heat jump ∆Cel./γTc = 1.34 is in good agreement with the nature of bulk superconductivity.

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Topics: Critical field (62%), Superconductivity (54%)

2 Citations

Open accessPosted ContentDOI: 10.1088/1361-6668/AC2169
Mebrouka Boubeche, N. L. Wang, Jianping Sun, Pengtao Yang  +7 moreInstitutions (1)
Abstract: We report the anomalous charge density wave (CDW) state evolution and dome-like superconductivity (SC) in CuIr2Te4-xSex series. Room temperature powder X ray-diffraction (PXRD) results indicate that CuIr2Te4-xSex compounds retain the same structure as the host CuIr2Te4 and the unit cell constants a and c manifest a linear decline with increasing Se content. Magnetization, resistivity and heat capacity results suggest that superconducting transition temperature (Tc) exhibits a weak dome-like variation as substituting Te by Se with the maximum Tc = 2.83 K for x = 0.1 followed by suppression in Tc and simultaneous decrease of the superconducting volume fraction. Unexpectedly, the CDW-like transition (TCDW) is suppressed with lower Se doping but re-emerges at higher doping. Meanwhile, the temperature-dependent XRD measurements show that the trigonal structure is stable at 20 K, 100 K and 300 K for the host sample and the doping composition with x = 0.5, thus we propose that the behaviour CDW-like transition arises from the disorder effect created by chemical doping and is not related to structural transition. The lower and the upper critical fields of these compounds are also addressed.

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57 results found

Open accessJournal ArticleDOI: 10.1038/NNANO.2010.279
Abstract: Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.

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Topics: Graphene nanoribbons (62%), Phosphorene (56%), Graphene (56%) ... read more

10,809 Citations

Journal ArticleDOI: 10.1021/JA800073M
Abstract: We report that a layered iron-based compound LaOFeAs undergoes superconducting transition under doping with F- ions at the O2- site. The transition temperature (Tc) exhibits a trapezoid shape dependence on the F- content, with the highest Tc of ∼26 K at ∼11 atom %.

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6,260 Citations

Journal ArticleDOI: 10.1103/PHYSREV.167.331
W. L. McMillan1Institutions (1)
10 Mar 1968-Physical Review
Abstract: The superconducting transition temperature is calculated as a function of the electron-phonon and electron-electron coupling constants within the framework of the strong-coupling theory. Using this theoretical result, we find empirical values of the coupling constants and the "band-structure" density of states for a number of metals and alloys. It is noted that the electron-phonon coupling constant depends primarily on the phonon frequencies rather than on the electronic properties of the metal. Finally, using these results, one can predict a maximum superconducting transition temperature.

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Topics: Room-temperature superconductor (59%), Coupling constant (55%), Transition temperature (55%) ... read more

3,570 Citations

Journal ArticleDOI: 10.1080/00018736900101307
Abstract: The transition metal dichalcogenides are about 60 in number. Two-thirds of these assume layer structures. Crystals of such materials can be cleaved down to less than 1000 A and are then transparent in the region of direct band-to-band transitions. The transmission spectra of the family have been correlated group by group with the wide range of electrical and structural data available to yield useful working band models that are in accord with a molecular orbital approach. Several special topics have arisen; these include exciton screening, d-band formation, and the metal/insulator transition; also magnetism and superconductivity in such compounds. High pressure work seems to offer the possibility for testing the recent theory of excitonic insulators.

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Topics: Metal K-edge (56%), Exciton (51%)

2,998 Citations

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