高压下三氢化硫H_3S的高温超导电性研究进展

Review of High Temperature Superconductivity of Sulphur Trihydrides H_3S under High Pressure

高压下富氢材料的压致金属化和超导电性是实现金属氢和高温超导体的有效途径,已经成为物理学、材料科学等多学科的热点研究领域之一。最近在高压下发现的三氢化硫(H_3S),因其200 K的超导转变温度刷新了高温超导纪录,向室温超导体的实现迈出重要的一步,引起了国际上的广泛关注。是什么使得H_3S如此特殊?它的创纪录的Tc、简单的晶体结构和奇异电子态密度使得H_3S成为潜在的高温超导材料,进一步推动了人们对高压下富氢材料超导电性的研究。在过去两年时间内,人们通过各种实验技术和理论方法研究H_3S在高压下的超导电性、同位素效应、元素的掺杂效应、探索超导的内在物理原因等等。目前理论和实验都一致认为高压下可以通过两种途径获得H_3S:3H_2S→2H_3S+S,2H_2S+H_2→2H_3S。对高温超导体H_3S的发现、影响H_3S高温超导的内在物理原因、同位素效应随压力的变化、掺杂对H_3S超导转变温度的影响以及高压下硫化氢(H_2S)的分解进行简要介绍。

Hydrogen-rich materials which are potential high-temperature superconductors,and also believed to be an effective way to the metallization of hydrogen,have attracted significant interest in lots of fields,such as physics,material science and so on. Recently,the discovery of high-pressure superconductivity of sulphur trihydrides( H_3S) has set a record at 200 K and attracted wide attention. What makes the H_3S so special? Its high Tc,simple crystal structure,and novel density of states make H_3S be potential high temperature superconductor,and inspire further efforts to research the superconductivity of hydrogen-rich materials. During last two years,the superconductivity,isotopic effect,element doping effect,the inner physical relationship have been studied by means of the high pressure experimental measurements and first-principles calculations.Recently,a consensus has been reached between theroretical and experimental studies that H_3S that hardly occurs at atmospheric pressure can be formed at high pressure by two main ways: 3H_2S→2H_3S+S,2H_2S+H2→2H_3S. In this work,the discovery of high temperature superconductor H_3S,the inner relationship between crystal structure,electronic structure and superconductivity,the pressure dependence of isotope effect,the influence of doping on superconducting transition temperature of H_3S,and the decomposition of H2S under high pressure have been discussed.