Two kinds of glassy sulfurs are synthesized by thrapid compression method from liquid sulfur at temperatures below and above the X-transition point. The glassy sulfur has different colors and transparencies, depending...Two kinds of glassy sulfurs are synthesized by thrapid compression method from liquid sulfur at temperatures below and above the X-transition point. The glassy sulfur has different colors and transparencies, depending on temperature, which may inherit some structural information from the transition. Raman spectrum studies of these samples show that a large fraction of polymeric chains exist in the glassy sulfur, even in the one solidified from T 〈 Tλ. We find that a higher compression rate instead of a higher temperature of the parent liquid captures more polymeric chains. Pressure-induced glassy sulfur presents high thermal stability compared with temperature quenched glassy sulfur and could transform into liquid sulfur directly without crystallization through an abnormal exothermic melting course. High energy x-ray diffraction is utilized to study the local order of the pressure-induced glassy sulfur.展开更多
We perform a series of high-pressure synchrotron x-ray diffraction （XRD） and resistance measurements on the Weyl semimetal NbAs. The crystal structure remains stable up to 26 GPa according to the powder XRD data. Th...We perform a series of high-pressure synchrotron x-ray diffraction （XRD） and resistance measurements on the Weyl semimetal NbAs. The crystal structure remains stable up to 26 GPa according to the powder XRD data. The resistance of NbAs single crystal increases monotonically with pressure at low temperature. Up to 20 GPa, no superconducting transition is observed down to 0.3 K. These results show that the Weyl semimetal phase is robust in NbAs, and applying pressure may not be a good way to obtain a topological superconductor from Weyl semimetal NbAs.展开更多
基金supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U1530402)the National Natural Science Foundation of China(Grant No.11004163)+2 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.2682014ZT31)the Department of Energy National Nuclear Security Administration(Grant No.DE-NA0001974)the Department of Energy Basic Energy Sciences(Grant Nos.DE-FG02-99ER45775and DE-AC02-06CH11357)
文摘Two kinds of glassy sulfurs are synthesized by thrapid compression method from liquid sulfur at temperatures below and above the X-transition point. The glassy sulfur has different colors and transparencies, depending on temperature, which may inherit some structural information from the transition. Raman spectrum studies of these samples show that a large fraction of polymeric chains exist in the glassy sulfur, even in the one solidified from T 〈 Tλ. We find that a higher compression rate instead of a higher temperature of the parent liquid captures more polymeric chains. Pressure-induced glassy sulfur presents high thermal stability compared with temperature quenched glassy sulfur and could transform into liquid sulfur directly without crystallization through an abnormal exothermic melting course. High energy x-ray diffraction is utilized to study the local order of the pressure-induced glassy sulfur.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11422429 and 11421404the National Basic Research Program of China under Grant Nos 2012CB821402 and 2015CB921401+5 种基金the China Postdoctoral Science Foundation under Grant No 2014M560288the Program for Professor of Special Appointment(Eastern Scholar) at Shanghai Institutions of Higher Learningthe Science and Technology Commission of Shanghai Municipality of China under Grant No 15XD1500200HPCAT operations are supported by DOE-NNSA under Award No DE-NA0001974DOE-BES under Award No DE-FG02-99ER45775partial instrumentation funding by NSF
文摘We perform a series of high-pressure synchrotron x-ray diffraction （XRD） and resistance measurements on the Weyl semimetal NbAs. The crystal structure remains stable up to 26 GPa according to the powder XRD data. The resistance of NbAs single crystal increases monotonically with pressure at low temperature. Up to 20 GPa, no superconducting transition is observed down to 0.3 K. These results show that the Weyl semimetal phase is robust in NbAs, and applying pressure may not be a good way to obtain a topological superconductor from Weyl semimetal NbAs.
