Enhanced Superconductivity in Pressure Quench in In2Se3 – Dr. Feng Ke

JULY 11, 2017

Pressure induced superconductivity has been realized in several systems, while the superconductivity will disappear with pressure quench. So how to preserve the pressure-induced superconductivity remains a problem to be solved. New research from HPSTAR revealed that enhanced superconductivity happened in In2Se3 during pressurequench.This opens up a possible route to preserve the high-temperature superconductors induced by compression to low and even ambient pressure. Their work is published by Advanced Materials.

Since the first discovery of superconductivity in mercury in 1911, making new superconductor with higher superconducting transition temperature (Tc) has been the Holy Grail of the superconductor academia and industries.

“Pressure is a paramount significance for promoting superconducting transition temperature and making new types of superconductors, as exemplified by the superconducting transition of cuprate oxides and hydrogen sulphide system occurring at 165 and 203 kelven, respectively”, said Dr. Feng Ke who led the research.

“However, how to preserve the pressure-promoted superconductivity to low and even ambient pressure for practical applications is a long-term chanllenge” added Dr. Bin Chen, a staff scientist of HPSTAR and one corresponding author of this study.

The researchers from multiple institutions of China and the United States have conducted a step study toward this goal. They observed striking superconducting temperature evolution during compression.

“The most surprising is that the superconductivity of In2Se3 that occurs at ~43.1 gigapascals duringcompression still remains robust during pressure quenching, with a twofold increase at a lower decompression pressure”, said Dr. Feng Ke.

“This much desired superconductivity enhancement in pressure quench can be attributed to the significant softening of phonon frequency in decompression and the irreversible layered or two-dimensional to three-dimensional structural transition of the high-pressure phases”, explained Dr. Feng Ke.

Their findings provide guidance in search for pressure-quenchable superconductors: In2Se3-like low-dimensional layered materials which can keep relatively higher carrier concentration for electron-phonon coupling at lower decompression pressure may also demonstrate significant decompression-driven superconductivity enhancement.

“If quenchable pressure is sufficiently low, around a few gigapascals, some other approaches such as introducing chemical pressure may undertake the last-mile work of maintain high-pressure superconductivity in a practical condition, making possible the real application of pressure-induced superconductors”, Dr. Bin Chen added, “More explorations are going on”.

Caption: Left: The microphotography of the layered In2Se3 for high-pressure electrical transport measurements; Right: Tc of In2Se3of different pressure cycles, courtesy of Dr. Feng Ke.

Media reports:

科学网：http://paper.sciencenet.cn/htmlpaper/20177131151291044454.shtm?id=44454

科技日报：http://stdaily.com/index/kejixinwen/2017-07/13/content_559650.shtml

实现高温、室温超导是超导学术界和工业界梦寐以求的圣杯。借助高压技术，创纪录的超导转变温度165 K和203 K先后在铜氧化物和硫化氢上实现。但遗憾的是，压力诱导的超导现象随着压力的卸除一起消失了。北京高压科学研究中心的柯峰博士及合作者最近观察到二维材料硒化铟压力诱导的超导行为在降压过程中反而增强了，超导温度比升压过程中的高了近一倍，并且维持到了很低的压力。这个鼓舞人心的结果表明合适地选择材料，高压诱导的高温超导现象可以保持至低压甚至室压条件下，使高压超导的应用成为可能。该结果今年七月十号发表在著名国际材料学术期刊《AdvancedMaterials》上。