Electron- and hole-doping on ScH$_{2}$ and YH$_{2}$: Effects on superconductivity without applied pressure

S. Villa-Cortés; O. De la Peña-Seaman

doi:10.1088/1361-648X/ac17ae

paper

Electron- and hole-doping on ScH $_{2}$ and YH $_{2}$ : Effects on superconductivity without applied pressure

arXiv:2106.10379 · doi:10.1088/1361-648X/ac17ae

Abstract

We present the evolution of the structural, electronic, and lattice dynamical properties, as well as the electron-phonon coupling and superconducting critical temperature ( $T_{c}$ ) of ScH $_{2}$ and YH $_{2}$ metal hydrides solid solutions, as a function of the electron- and hole-doping content. The study was performed within the density functional perturbation theory, taking into account the effect of zero-point energy through the quasi-harmonic approximation, and the solid solutions Sc $_{1 - x} M_{x}$ H $_{2}$ ( $M$ =Ca,Ti) and Y $_{1 - x} M_{x}$ H $_{2}$ ( $M$ =Sr,Zr) were modeled by the virtual crystal approximation. We have found that, under hole-doping ( $M$ =Ca,Sr), the ScH $_{2}$ and YH $_{2}$ hydrides do not improve their electron-phonon coupling properties, sensed by $λ (x)$ . Instead, by electron-doping ( $M$ =Ti,Zr), the systems reach a critical content $x \approx 0.5$ where the latent coupling is triggered, increasing $λ$ as high as $70%$ , in comparison with its $λ (x = 0)$ value. Our results show that $T_{c}$ quickly decreases as a function of $x$ on the hole-doping region, from $x = 0.2$ to $x = 0.9$ , collapsing at the end. Alternatively, for electron-doping, $T_{c}$ first decreases steadily until $x = 0.5$ , reaching its minimum, but for $x > 0.5$ it increases rapidly, reaching its maximum value of the entire range at the Sc $_{0.05}$ Ti $_{0.95}$ H $_{2}$ and Y $_{0.2}$ Zr $_{0.8}$ H $_{2}$ solid solutions, demonstrating that electron-doping can improve the superconducting properties of pristine metal hydrides, in the absence of applied pressure.

8 pages, 8 figures

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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

Electron- and hole-doping on ScH2​ and YH2​: Effects on superconductivity without applied pressure

Abstract

References in corpus (5)

Cited by in corpus (1)

Electron- and hole-doping on ScH $_{2}$ and YH $_{2}$ : Effects on superconductivity without applied pressure