From ultrasoft pseudopotentials to the projector augmented-wave method
TL;DR: In this paper, the formal relationship between US Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived and the Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional.
Abstract: The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Bl\"ochl's projector augmented wave (PAW) method is derived. It is shown that the total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addition, critical tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed core all electron methods. These tests include small molecules $({\mathrm{H}}_{2}{,\mathrm{}\mathrm{H}}_{2}{\mathrm{O},\mathrm{}\mathrm{Li}}_{2}{,\mathrm{}\mathrm{N}}_{2}{,\mathrm{}\mathrm{F}}_{2}{,\mathrm{}\mathrm{BF}}_{3}{,\mathrm{}\mathrm{SiF}}_{4})$ and several bulk systems (diamond, Si, V, Li, Ca, ${\mathrm{CaF}}_{2},$ Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
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TL;DR: In this article, a single-atom platinum immobilized NiO/Ni heterostructure (PtSA-NiO//Ni) was developed as an alkaline hydrogen evolution catalyst.
Abstract: Single-atom catalysts provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However, the sluggish activity of the catalysts for alkaline water dissociation has hampered advances in highly efficient hydrogen production. Herein, we develop a single-atom platinum immobilized NiO/Ni heterostructure (PtSA-NiO/Ni) as an alkaline hydrogen evolution catalyst. It is found that Pt single atom coupled with NiO/Ni heterostructure enables the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*), which efficiently tailors the water dissociation energy and promotes the H* conversion for accelerating alkaline hydrogen evolution reaction. A further enhancement is achieved by constructing PtSA-NiO/Ni nanosheets on Ag nanowires to form a hierarchical three-dimensional morphology. Consequently, the fabricated PtSA-NiO/Ni catalyst displays high alkaline hydrogen evolution performances with a quite high mass activity of 20.6 A mg−1 for Pt at the overpotential of 100 mV, significantly outperforming the reported catalysts. While H2 evolution from water may represent a renewable energy source, there is a strong need to improve catalytic efficiencies while maximizing materials utilization. Here, authors examine single-atom Pt on nickel-based heterostructures as highly active electrocatalysts for alkaline H2 evolution.
243 citations
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TL;DR: In this article, the binding enthalpies of 14 different small molecules in a series of isostructural metal-organic frameworks, M-MOF-74, with M = Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn.
Abstract: Using density functional theory, we systematically compute and investigate the binding enthalpies of 14 different small molecules in a series of isostructural metal–organic frameworks, M-MOF-74, with M = Mg, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. The small molecules we consider include major flue-gas components, trace gases, and small hydrocarbons, i.e., H2, CO, CO2, H2O, H2S, N2, NH3, SO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8. In total, the adsorption energetics of 140 unique systems are presented and discussed. Dispersion interactions are included by employing a nonlocal van der Waals density functional, vdW-DF2. Hubbard U corrections are applied to the localized d electrons of transition metal atoms, and the impact of such corrections is assessed quantitatively. For systems for which measured binding enthalpies have been reported, our calculations lead to excellent overall agreement with experimentally determined structures and isosteric heats of adsorption. For systems that have yet to be realized or...
243 citations
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TL;DR: In this article, the authors applied density functional theory slab calculations in the investigation of the adsorption and hydrogenation of CO2 on the (110) surface of In2O3.
Abstract: Catalytic conversion of CO2 to liquid fuels or valuable chemicals is an attractive alternative to geological sequestration. In the present study, we applied density functional theory slab calculations in the investigation of the adsorption and hydrogenation of CO2 on the (110) surface of In2O3. Our results indicate that the adsorbed CO2 is activated, forming a surface carbonate species by combining with surface oxygen, and has an adsorption energy of −1.25 eV. Heterolytic dissociative adsorption of H2 results in a surface hydroxyl from H binding the surface O site and a hydride from H binding the In site. The migration of H from the In site to the neighboring O site is energetically favorable but has a significant activation barrier of 1.32 eV. Water may adsorb on the surface either molecularly or dissociatively, with adsorption energy of −0.83 eV and −1.19 eV, respectively. Starting from CO2 coadsorbed with the H adatoms on the In2O3 surface, we examined two possible conversion pathways for CO2: (a) CO2 ...
243 citations
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TL;DR: In this paper, the structural and electronic properties of group IV (C,SiC, Si, Ge, and Sn) graphene-like sheets in flat and buckled configurations and the respective hydrogenated or fluorinated graphane-like ones were investigated.
Abstract: We performed a first-principles investigation on the structural and electronic properties of group IV (C, SiC, Si, Ge, and Sn) graphene-like sheets in flat and buckled configurations and the respective hydrogenated or fluorinated graphane-like ones. The analysis on the energetics, associated with the formation of those structures, showed that fluorinated graphane-like sheets are very stable and should be easily synthesized in the laboratory. We also studied the changes of the properties of the graphene-like sheets as a result of hydrogenation or fluorination. The interatomic distances in those graphane-like sheets are consistent with the respective crystalline ones, a property that may facilitate integration of those sheets within three-dimensional nanodevices.
242 citations
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TL;DR: In this paper, the authors reported the observation of bulk superconductivity in single crystals of the two-dimensional kagome metal (KV, Rb, Cs) with magnetic susceptibility, resistivity, and heat capacity measurements.
Abstract: Here we report the observation of bulk superconductivity in single crystals of the two-dimensional kagome metal ${\mathrm{KV}}_{3}{\mathrm{Sb}}_{5}$. Magnetic susceptibility, resistivity, and heat capacity measurements reveal superconductivity below ${T}_{c}=0.93\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, and density functional theory (DFT) calculations further characterize the normal state as a ${\mathbb{Z}}_{2}$ topological metal. Our results demonstrate that the recent observation of superconductivity within the related kagome metal ${\mathrm{CsV}}_{3}{\mathrm{Sb}}_{5}$ is likely a common feature across the $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ ($A$: K, Rb, Cs) family of compounds and establishes them as a rich arena for studying the interplay between bulk superconductivity, topological surface states, and likely electronic density wave order in an exfoliable kagome lattice.
242 citations
References
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31 Dec 1993
TL;DR: The linearized augmented planewave (LAPW) method has emerged as the standard by which density functional calculations for transition metal and rare-earth containing materials are judged.
Abstract: With its extreme accuracy and reasonable computational efficiency, the linearized augmented planewave (LAPW) method has emerged as the standard by which density functional calculations for transition metal and rare-earth containing materials are judged. This volume presents a thorough and self-conta
1,150 citations