Tunable Superconductivity in 2H-NbSe2 via In Situ Li Intercalation  

作　　者：Kaiyao Zhou Jun Deng Liwei Guo Jiangang Guo 周楷尧;邓俊;郭丽伟;郭建刚(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Songshan Lake Materials Laboratory,Dongguan 523808,China)

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Chinese Physics Letters》2020年第9期78-83,共6页中国物理快报（英文版）

基　　金：Supported by the Mo ST-Strategic International Cooperation in Science,Technology and Innovation Key Program(Grant No.2018YFE0202601);the National Key Research and Development Program of China(Grant Nos.2017YFA0304700 and2016YFA0300600);the National Natural Science Foundation of China(Grant Nos.51922105 and 51772322);the Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SLH013)。

摘　　要：Using the newly-developed solid ionic gating technique,we measure the electrical transport property of a thinflake NbSe2 superconductor(Tc=6.67 K)under continuous Li intercalation and electron doping.It is found that the charge-density-wave transition is suppressed,while at the same time a carrier density,decreasing from7×10^14 cm^-2 to 2×10^14 cm^-2 also occurs.This tunable capability in relation to carrier density is 70%,which is 5 times larger than that found using the liquid ionic gating method[Phys.Rev.Lett.117(2016)106801].Meanwhile,we find that the scattering type of conduction electrons transits to the s-d process,which may be caused by the change of the occupied states of 4 d-electrons in Nb under the condition of Li intercalation.Simultaneously,we observe a certain decrement of electron-phonon coupling(EPC),based on the electron-phonon scattering model,in the high temperature range.Based on data gathered from in situ measurements,we construct a full phase diagram of carrier density,EPC and Tc in the intercalated NbSe2 sample,and qualitatively explain the variation of Tc within the BCS framework.It is our opinion that the in situ solid ionic gating method provides a direct route to describing the relationship between carrier density and superconductivity,which is helpful in promoting a clearer understanding of electronic phase competition in transition metal dichalcogenides.

关 键 词：NbSe2 SCATTERING SUPERCONDUCTOR 

分 类 号：O469[理学—凝聚态物理]