434 / 2019-03-02 10:09:17

Probing the high-pressure structure of TaH3 via CALYPSO

Structure prediction; Superconductivity; Transition metal hydrides

全体主题 > High Pressure Physics and Materials Science

It's a long-held dream for scientists to search room-temperature superconductivity. In 2004, Ashcroft scientifically suggested that compressed H-rich materials have the potential for becoming the good candidate for high-temperature superconductivity. As we known, the addition of a second element to hydrogen could reduce the physical pressure required to metallize the system via “chemical precompression”. The wisdom makes the metallization of hydrogen-dominated materials come true in the diamond-anvil cell (DAC). The suggestion has provoked a wave of searching for superconductivity in a flurry of hydrogen-dominated materials under high pressure. Recently, the remarkable theoretical prediction and subsequent experimental discovery of superconductivity 203K in hydrogen sulfide under high pressure rekindled the century-old dream of a room temperature superconductor. It is well known that the hydrides of d metals are formed in wide concentration ranges. Thus, the transition metal hydrides have also been the object of many investigations.
Herein, we predicted the highly symmetrical cubic TaH3 phase by using our in-house developed CALYPSO structure prediction method in conjunction with first-principles density functional calculations. At the same time, the experimental X ray diffraction also validates our computed results. Our swarm-intelligence based CALYPSO structural prediction calculations has been benchmarked on a variety of known high-pressure structures and has made several successful predictions about high-temperature superconductivity, for example, CaH6, LaH10 et al. The present results not only verify the reliability of CALYPSO, but also give the vital insight into intensively studying about the transition metal hydrides.