Superconductivity in high-pressure SiH ₄

Abstract

A combination of static and dynamical first-principles electronic calculations of silane, SiH4, at high pressure has revealed a novel monoclinic structure with C2/c symmetry. This highpressure phase is metallic and composed of layers of SiH4 bridged by H bonds. Perturbative linear response calculations at 90 and 125 GPa predict large electron-phonon couplings yielding an electron-phonon coupling parameter λ close to 0.9. The application of McMillan equation gives a superconducting critical temperature (Tc) between 45 and 55 K.

Superconducting high-pressure phase of platinum hydride from first principles

“…15 This discovery gives a well explanation for the differences between experimental and theoretical studies of high pressure phase of silane. 6,8,10,11,14 The calculated lattice constants, the simulated XRD pattern, and the superconducting transition temperature for platinum hydride are in good agreement with the previously published experimental results. 14 This finding will give rise to much interest exploring new possible mechanisms of the anomalous superconducting transition behavior in high pressure phase of silane or exploring other possible superconducting high pressure phases of new metal hydrides.…”

“…3 Recently, it was suggested that hydrogen-rich group IV hydrides can be metalized at much lower pressures because of the "chemical precompression" caused by the group IV atoms. [4][5][6][7][8][9][10][11] Therefore, much theoretical and experimental effort has focused on the possibility of attaining high-temperature superconductivity in group IV hydrides. The particular interesting is the case of silane (SiH 4 ), which was predicted to have at least seven phases.…”

Phonon Dispersion Analysis as an Indispensable Tool for Predictions of Solid State Polymorphism and Dynamic Metastability: Case of Compressed Silane

“…Initially we verified the phonon stability for a broad spectrum of the earlier reported structures [5,7,[13][14][15]. The calculations show that the seemingly simple SiH 4 system has a very complicated PES as all of the examined structures exhibit phonon instabilities for at least one pressure point from the range 15-125 GPa [19].…”

“…Previous theoretical studies [11][12][13][14][15][16] were concentrated on establishing the structure of the claimed metallic form of silane. For this a wide range of strategies of screening the potential energy surface (PES) of this system have been employed: chemical intuition [13], procedure of random sampling [14], molecular dynamics [15] and evolutionary algorithm [16].…”

“…For this a wide range of strategies of screening the potential energy surface (PES) of this system have been employed: chemical intuition [13], procedure of random sampling [14], molecular dynamics [15] and evolutionary algorithm [16]. In the present study we adopted an alternative strategy for finding the lowest--enthalpy structure of silane.…”