Superconductivity by doping in alkali-metal hydrides without applied pressure: An 
<i>ab initio</i>
 study

Olea-Amezcua, M.A.; Peña-Seaman, O. De la; Heid, R.

doi:10.1103/physrevb.99.214504

Cited by 14 publications

(30 citation statements)

References 43 publications

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“…The recent progress on this theme can be found in review articles [21][22][23][24][25][26][27]. However, ternary hydrides might also be potential high-temperature superconductors [28][29][30][31][32][33], and some studies have shown that they not only show high superconducting transition temperatures (T c ) but also exhibit unexpected superconducting mechanisms. For example, the predicted ternary hydride MgSiH 6 has a T c value of 63 K at 250 GPa, and its superconducting transition mainly comes from phonon softenings along → X and → M directions [34].…”

Section: Introductionmentioning

confidence: 99%

Phase diagrams and electronic properties of B-S and H-B-S systems under high pressure

Zhang

Lin

et al. 2019

Phys. Rev. B

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Pressure has become an effective way to obtain new materials with desirable properties. Considering the various stoichiometries, wide applications, and unique structures of binary H-S, H-B, and B-S compounds, especially at high pressures, it is worth expecting that they might form ternary compounds with interesting properties as well. Here, phase stabilities of H-B-S ternary compounds, in the pressure range from 0 to 200 GPa, are reliably determined through first-principles unbiased structural search calculations. A hitherto unknown orthorhombic HBS compound with Ama2 symmetry is identified to be stable above 25 GPa, in which B and S atoms alternate to form distorted chains and H atoms are covalently bonded with Bs. With pressure, Ama2 HBS undergoes a semiconductor-to-metal electronic transition and even becomes superconducting. The exploration of the binary B-S phase diagram indicates that B-S compounds tend to decompose into elemental solids above 208 GPa. However, two S-rich phases, B 2 S 3 and BS 2 , are predicted at low pressures, exhibiting semiconducting and metallic properties, respectively. BS 2 shows a calculated T c value of 21.9 K at 200 GPa, becoming a superconductor among bulk binary B-S compounds.

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Section: Introductionmentioning

confidence: 99%

Phase diagrams and electronic properties of B-S and H-B-S systems under high pressure

Zhang

Lin

et al. 2019

Phys. Rev. B

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“…In effect, the P6 3 cm structure has a tendency to transform into the P6 3 /mcm structure at this very pressure. The inclusion of ZPE calculation apparently plays a crucial role in determining the stable structure of Li 5 MoH 11 under pressure, as previously demonstrated in other metal hydride systems 39 , 40 . Regarding the R 3 c phase, the responsible pressure-dependent phonon dispersion displays a tiny soft-mode at the -point which is shown in Fig.…”

Section: Resultsmentioning

confidence: 59%

Stabilization and electronic topological transition of hydrogen-rich metal Li5MoH11 under high pressures from first-principles predictions

Tsuppayakorn‐aek

Sukmas

Ahuja

et al. 2021

Sci Rep

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Regarded as doped binary hydrides, ternary hydrides have recently become the subject of investigation since they are deemed to be metallic under pressure and possibly potentially high-temperature superconductors. Herein, the candidate structure of Li5MoH11 is predicted by exploiting the evolutionary searching. Its high-pressure phase adopts a hexagonal structure with P63/mcm space group. We used first-principles calculations including the zero-point energy to investigate the structures up to 200 GPa and found that the P63cm structure transforms into the P63/mcm structure at 48 GPa. Phonon calculations confirm that the P63/mcm structure is dynamically stable. Its stability is mainly attributed to the isostructural second-order phase transition. Our calculations reveal the electronic topological transition displaying an isostructural second-order phase transition at 160 GPa as well as the topology of its Fermi surfaces. We used the projected crystal orbital Hamilton population (pCOHP) to examine the nature of the chemical bonding and demonstrated that the results obtained from the pCOHP calculation are associated with the electronic band structure and electronic localized function.

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“…Fourier interpolation of dynamical matrices, calculated on a 8 × 8 × 8 q-point mesh, were used to de- termine the complete phonon spectra of the studied systems. Corrections due to quantum fluctuations at zero temperature, zero-point energy (ZPE) effects, are estimated through the quasi-harmonic approximation (QHA) [30,41]. Within this approximation, the phonon contribution to the ground-state energy is taken into account and then a equation of state for each concentration x can be constructed.…”

Section: Computational Detailsmentioning

confidence: 99%

“…In that work, the dopant acts as a donor which delivers electrons to the system, obtaining a n-doped material with a T c = 7.78 K for an electron content as high as 2.06, calculated at ambient pressure. Another work on that direction was performed by Olea-Amezcua et al [30]. There the authors showed the metallization of alkali-metal hydrides LiH, NaH, and KH by doping with alkaline-earth metals Be, Mg, and Ca, respectively, and analyzed the superconducting properties as a function of metal content.…”

Section: Introductionmentioning

confidence: 99%

“…Under this approach we are able to trace down the evolution of the structural, electronic, and lattice dynamical properties, as well as the el-ph coupling and T c , as a function of metal content, by inducing holes (p-doped) and electrons (n-doped), as well as applied pressure, of the proposed systems. Such approach is done by the construction of solid solutions with the metal atom of the hydride: Sc 1−x M x H 3 (M=Ca,Ti) and Y 1−x M x H 3 (M =Sr,Zr) within the Density Functional Theory (DFT) [32], using the virtual crystal approximation (VCA) [33], which has been successfully applied on the study of doped superconductors [30,[34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity on ScH$_{3}$ and YH$_{3}$ hydrides: Effects of applied pressure in combination with electron- and hole-doping on the electron-phonon coupling properties

Villa-Cortés,

De la Peña-Seaman

2021

Preprint

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The implementation of electron-and hole-doping, in conjunction to applied pressure, is analyzed as a mechanism to induce or enhance the superconducting state on fcc YH3 and ScH3. In particular, the evolution of their structural, electronic, and lattice dynamical properties, as well as the electron-phonon coupling and superconducting critical temperature (Tc) is presented and discussed, as a function of the electron-and hole-doping content as well as applied pressure. The study was performed within the density functional perturbation theory, taking into account the effects of zero-point energy through the quasi-harmonic approximation, while the doping was implemented by means of the construction of the Sc1−xMxH3 (M=Ca,Ti) and Y1−xMxH3 (M=Sr,Zr) solid solutions modeled with the virtual crystal approximation (VCA). We found that the ScH3 and YH3 hydrides shown a significant improvement of their electron-phonon coupling properties under hole-doping (M=Ca,Sr) and at pressure values close to dynamical instabilities. Instead, by electron-doping (M=Ti,Zr), the systems do not improve such properties, whatever value of applied pressure is considered. Then, as a result, Tc rapidly increases as a function of x on the hole-doping region, reaching its maximum value of 92.7(67.9) K and 84.5(60.2) K at x = 0.3 for Sc1−xCaxH3 at 10.8 GPa and Y1−xSrxH3 at 5.8 GPa respectively, with µ * = 0(0.15), while for both, electron-and hole-doping, Tc decreases as a function of the applied pressure, mainly due to phonon hardening. By the thorough analysis of the electron-phonon properties as a function of doping and pressure, we can conclude that the tuning of the lattice dynamics is a promising path for improving the superconductivity on both systems.

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Superconductivity by doping in alkali-metal hydrides without applied pressure: An ab initio study

Cited by 14 publications

References 43 publications

Phase diagrams and electronic properties of B-S and H-B-S systems under high pressure

Phase diagrams and electronic properties of B-S and H-B-S systems under high pressure

Stabilization and electronic topological transition of hydrogen-rich metal Li5MoH11 under high pressures from first-principles predictions

Superconductivity on ScH$_{3}$ and YH$_{3}$ hydrides: Effects of applied pressure in combination with electron- and hole-doping on the electron-phonon coupling properties

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