Effects of disorder and hydrostatic pressure on charge density wave and superconductivity in 2H−TaS2

作     者：Shuxiang Xu Jingjing Gao Ziyi Liu Keyu Chen Pengtao Yang Shangjie Tian Chunsheng Gong Jianping Sun Mianqi Xue Jun Gouchi Xuan Luo Yuping Sun Yoshiya Uwatoko Hechang Lei Bosen Wang Jinguang Cheng 

作者机构：Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100190 China Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China Science Island Branch of Graduate School University of Science and Technology of China Hefei 230026 China Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices Renmin University of China Beijing 100872 China Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China Institute for Solid State Physics University of Tokyo Kashiwanoha 5-1-5 Kashiwa Chiba 277–8581 Japan High Magnetic Field Laboratory Chinese Academy of Sciences Hefei 230031 China Collaborative Innovation Center of Microstructures Nanjing University Nanjing 210093 China Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2021年第103卷第22期

页      面：224509-224509页

核心收录：

基　　金：Excellence and Scientific Research Grant of Hefei Science Center of CAS, (2018HSC-UE011) IOP Hundred-Talent Program, (Y7K5031X61) Key Research Program of Frontier Sciences, CAS, (QYZDB-SSW-SLH015) Outstanding Innovative Talents Cultivation Funded Programs 2020 of Renmin University Of China, (U1832141, U1932217) Youth Promotion Association of CAS, (2018010) National Natural Science Foundation of China, NSFC, (11574377, 11674326, 11774423, 11822412, 11834016, 11874357, 11874400, 11921004, 51171177) National Natural Science Foundation of China, NSFC Chinese Academy of Sciences, CAS, (QYZDB-SSWSLH013, XDB25000000, XDB33000000) Chinese Academy of Sciences, CAS Renmin University of China, RUC, (18XNLG14, 19XNLG17, 20XNH062) Renmin University of China, RUC Natural Science Foundation of Beijing Municipality, (Z190008, Z200005) Natural Science Foundation of Beijing Municipality National Key Research and Development Program of China, NKRDPC, (2016YFA0300404, 2016YFA0300504, 2018YFA0305700, 2018YFA0305800, 2018YFE0202600) National Key Research and Development Program of China, NKRDPC Fundamental Research Funds for the Central Universities 

主　　题：Charge density waves Electrical properties Magnetic susceptibility Pressure effects Superconductivity Pressure techniques 

摘      要：We report the comparative effects of disorder and hydrostatic pressure on charge density wave (CDW) and superconductivity (SC) in 2H−TaS2 by measuring electrical resistivity and ac magnetic susceptibility. For the crystals in the clean limit (low disorder level), CDW ground state is suppressed completely at a critical pressure Pc∼6.24(5)GPa where a dome-shaped pressure dependence of superconducting transition temperature Tc(P) appears with a maximum value of Tcmax∼9.15K, indicating strong competitions between CDW and SC. The temperature exponent n of low-temperature resistivity data decreases from ∼3.36 at ambient pressure (AP) to ∼1.29(2) at Pc and then retains a saturated value ∼2.10(4) when the pressure is higher than 7.5 GPa; accordingly, the quadratic temperature coefficient of normal-state resistivity A peaks out just at Pc with an enhancement by nearly one order in magnitude. These features strongly manifest that the enhanced critical CDW fluctuations near Pc are possible important glues for superconducting pairings. High-pressure magnetic susceptibility indicates that superconducting shielding volume increases with pressure and retains a nearly constant value above Pc, which evidences that the enhancement of Tc(P) is accompanied by the expense of CDW. For those crystals in dirty limit (high disorder level), there is no clear CDW phase transition in resistivity; the pressure dependence of Tc(P) and n broadens up and becomes less apparent in comparison with the clean crystals. Our results suggest that disorder scattering and the melting of CDW are two factors affecting SC, and the melting of CDW dominates the change of Tc below Pc; the enhancement of Tc(P) is associated with the suppression of CDW by pressure and the increase in the density of states at Fermi level; however, after the CDW collapse, superconducting pairing strength is strongly weakened by impurity scattering above Pc according to Anderson s theorem.