Superconductivity of hydrogen superoxide under high pressure

Abstract

We explored the superconductivity in a oxygen-hydrogen binary system, H h O1 − h , under highpressure using an evolutionary algorithm-based materials informatics approach. We searched for metallic and superconducting phases in pressures up to 300 GPa using a crystal structure prediction technique based on a genetic algorithm and first-principles calculations, and found that hydrogen superoxide (HO2) with an orthorhombic Pnnm, which emerges as a metastable compound in pressure above 180 GPa, is the only compound showing the superconductivity. The superconducting critical temperature T c is 9.78 K at 200 GPa, which is higher than that of pure solid oxygen, 2.87 K, due to the effect of the hydrogenation. We confirmed that the T c value shows a good agreement with potential superconducting critical temperature T c p o t estimated by the superconductivity predictor, which we have previously developed by a genetic programming using 497 first-principles datasets of other binary hydrides. Moreover, supposing that all the H h O1 − h compounds are superconductors at pressures in 150–200 GPa, we investigated the potential superconductivity of the H h O1 − h system using the predictor and obtained that T c p o t shows 10 K for h = 0.033 3 and increases to 100 K with the increase of h to 0.966 7.

The electron-phonon coupling constant, Fermi temperature and unconventional superconductivity in the carbonaceous sulfur hydride 190 K superconductor

“…Recently, Snider et al [11] reported on the observation that ternary compound Hx(S,C)y exhibits the transition temperature within a range of Tc = 275-287 K (at P = 258-270 GPa), which is by about 5 K higher than previous record of Tc = 280 K, reported by Somayazulu et al [8] in highly-compressed LaH10. While detailed phase/structural and phonon spectrum and other physical properties measurements [1][2][3][4][5][6][7]9,[12][13][14], as well as the first-principle calculation studies [2,6,[15][16][17][18][19][20][21][22][23][24][25][26][27] are on-going tasks for Hx(S,C)y compound [28], in this paper we report results of the analysis of temperature dependent magnetoresistance, R(T,B), from which we deduced:…”

The electron–phonon coupling constant and the Debye temperature in polyhydrides of thorium, hexadeuteride of yttrium, and metallic hydrogen phase III

“…where * is the Coulomb pseudopotential parameter (ranging from * = 0.10-0.16 [43][44][45][46][47][48][49][50][51][52][53][54]).…”

“…4-6 have a single solution in respect of 𝜆 𝑒−𝑝ℎ , for given T, Tc and *. Due to * is varying within a range of 0.10-0.16 [43][44][45][46][47][48][49][50][51][52][53][54], in this work we used the mean value of * = 0.13 in all calculations. There is a need to clarify, that we define Tc in Eqs.…”