Topological superconductivity is one of most fascinating properties of topological quantum matters that was theoretically proposed and can support Majorana Fermions at the edge state. Superconductivity was previously realized in a Cu-intercalated Bi2Se3 topological compound or a Bi2Te3 topological compound at high pressure. Here we report the discovery of superconductivity in the topological compound Sb2Te3 when pressure was applied. The crystal structure analysis results reveal that superconductivity at a low-pressure range occurs at the ambient phase. The Hall coefficient measurements indicate the change of p-type carriers at a low-pressure range within the ambient phase, into n-type at higher pressures, showing intimate relation to superconducting transition temperature. The first principle calculations based on experimental measurements of the crystal lattice show that Sb2Te3 retains its Dirac surface states within the low-pressure ambient phase where superconductivity was observed, which indicates a strong relationship between superconductivity and topology nature.

A new iron pnictide LiFeP superconductor was found. The compound crystallizes into a Cu2Sb structure containing an "FeP" layer showing superconductivity with maximum Tc of 6K. This is the first "111" type iron pnictide superconductor containing no arsenic. The new superconductor is featured with itinerant behavior at normal state that could be helpful to understand the novel superconducting mechanism of iron pnictide compounds.

Recently, A2B3 type strong spin orbital coupling compounds such as Bi2Te3, Bi2Se3 and Sb2Te3 were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb2Se3 on the other hand was found to be topological trivial, but further theoretical studies indicated that the pressure might induce Sb2Se3 into a topological nontrivial state. Here, we report on the discovery of superconductivity in Sb2Se3 single crystal induced via pressure. Our experiments indicated that Sb2Se3 became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at ~3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (TC) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. High pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of TC slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.

-The effect of pressure on superconductivity of "111" type Na 1-x FeAs is investigated through temperature dependent electrical resistance measurement in a diamond anvil cell. The superconducting transition temperature (T c ) increases from 26

Strong spin orbital interaction (SOI) can induce unique quantum phenomena such as topological insulators, the Rashba effect, or p-wave superconductivity. Combining these three quantum phenomena into a single compound has important scientific implications. Here we report experimental observations of consecutive quantum phase transitions from a Rashba type topological trivial phase to topological insulator state then further proceeding to superconductivity in a SOI compound BiTeI tuned via pressures. The electrical resistivity measurement with V shape change signals the transition from a Rashba type topological trivial to a topological insulator phase at 2 GPa, which is caused by an energy gap close then reopen with band inverse. Superconducting transition appears at 8 GPa with a critical temperature TC of 5.3 K. Structure refinements indicate that the consecutive phase transitions are correlated to the changes in the Bi–Te bond and bond angle as function of pressures. The Hall Effect measurements reveal an intimate relationship between superconductivity and the unusual change in carrier density that points to possible unconventional superconductivity.

The behavior of superconductivity of "111"-type iron pnictide superconductors, namely, LiFeAs, NaFeAs and LiFeP, is investigated at different pressures through electrical resistance measurements. For LiFeAs and LiFeP, the superconducting transition temperature T c decreases monotonously with increasing pressure, with the pressure coefficient of dT c /dP being −1.38 and −1.26 K/GPa, respectively. The T c of NaFeAs increases to a maximum value with the pressure increasing to 3 GPa; further increasing the pressure suppresses T c with the slope of dT c /dP about −3.40 K/GPa.

A series of LiFe 1−x CuxAs single crystal with the doping level x = 0-0.16 were grown. The resistivity measurement was conducted. The results show that the 10% Cu doping completely suppresses superconducting transition temperature and when the doping level increases to 16%, it presents a semiconducting behavior in the region of 2 K to 300 K.

An efficient all-solid-state picosecond (ps) ultraviolet (UV) laser at 335 nm was demonstrated based on frequency quadrupling of a mode-locked 1342 nm MOPA system. An output power of 0.95 W was obtained under a fundamental wave power of 16.38 W, corresponding to a conversion efficiency of 5.8% from infrared to UV. The repetition rate and pulse duration were 77 MHz and 20.2 ps, respectively. The beam quality factor M(2) was measured to be 1.56. This is, to the best of our knowledge, the highest output power at 335 nm.