Emergence of superconductivity in doped H2O ice at high pressure

Abstract

We investigate the possibility of achieving high-temperature superconductivity in hydrides under pressure by inducing metallization of otherwise insulating phases through doping, a path previously used to render standard semiconductors superconducting at ambient pressure. Following this idea, we study H2O, one of the most abundant and well-studied substances, we identify nitrogen as the most likely and promising substitution/dopant. We show that for realistic levels of doping of a few percent, the phase X of ice becomes superconducting with a critical temperature of about 60 K at 150 GPa. In view of the vast number of hydrides that are strongly covalent bonded, but that remain insulating up to rather large pressures, our results open a series of new possibilities in the quest for novel high-temperature superconductors.

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

“…As a matter of fact the class of molecular crystals containing light elements like carbon and hydrogen is immense and full of potential. Following this idea, Flores-Livas et al [487,488] studied H 2 O and polyethylene, identifying promising substitution/dopant and showing that for realistic levels of doping at high pressure, these covalent phases may exhibit superconductivity with critical temperature of about 60 K at moderate pressures. In view of the vast number of hydrides that are covalent bonded but remain insulating up to rather large pressures, this venue represent a promising route for hunting high-T c hydrides.…”

Route to a Superconducting Phase above Room Temperature in Electron-Doped Hydride Compounds under High Pressure

“…There have been few studies on the superconductivity of compressed ternary hydrides [27][28][29][30][31][32][33][34][35][36][37][38][39][40]. Experimental examples include BeReH 9 [27] and Li 5 MoH 11 [28] synthesized under high-pressure conditions and showing unexpectedly low T c < 10 K. Crystal structure prediction simulations for ternary systems are computationally demanding.…”

Understanding Novel Superconductors with Ab Initio Calculations

“…However, since ternary Gibb's diagrams are computationally much more expensive than binary convex hulls, fully ab-initio studies of ternaries are rare. Two recent studies explore two different strategies towards high-T c in ternary hydrides: doping low-pressure molecular phases of covalent binary hydrides, like water; [129] and off-stoichiometry phases of alkali-metal alanates and borates, which permit to independently tune the degree of metallicity and covalency. [130] Due to the intrinsic difficulty of reaching Megabar pressures, and the limited information that can be extracted from X-Ray spectra, the experimental information on high-pressure hydrides is much scarcer than theoretical predictions.…”

“…Fig. 10 Selected literature examples of possible strategies to room-temperature superconductivity at ambient pressures: (a) First-principles prediction of α and β -LiB [178] (Design by Analogy); (b) Superconductivity in doped ices [129] (Chemical Doping of molecular crystals); (c) Charge-density profile of superconducting Pb@Si(111) surface. [179] (Atomic-scale design and Dimensionality); (d) High-pressure superconducting phase diagram of phosphorus [101] (Quenching of High-pressure metastable phases); (e) T c vs field effect and chemical doping in monolayer MoS 2 [180] (Doping by field effect).…”