Titanium doped kagome superconductor CsV3-xTixSb5 and two distinct phases

Haitao Yang; Zihao Huang; Yuhang Zhang; Zhen Zhao; Jinan Shi; Hailan Luo; Lin Zhao; Guojian Qian; Hengxin Tan; Bin Hu; Ke Zhu; Zouyouwei Lu; Hua Zhang; Jianping Sun; Jinguang Cheng; Chengmin Shen; Xiao Lin; Binghai Yan; Xingjiang Zhou; Ziqiang Wang; Stephen J Pennycook; Hui Chen; Xiaoli Dong; Wu Zhou; Hong-Jun Gao

doi:10.1016/j.scib.2022.10.015

Titanium doped kagome superconductor CsV_3-_xTi_xSb₅ and two distinct phases

Sci Bull (Beijing). 2022 Nov 15;67(21):2176-2185. doi: 10.1016/j.scib.2022.10.015. Epub 2022 Oct 19.

Authors

Haitao Yang¹, Zihao Huang², Yuhang Zhang², Zhen Zhao², Jinan Shi³, Hailan Luo², Lin Zhao², Guojian Qian², Hengxin Tan⁴, Bin Hu², Ke Zhu², Zouyouwei Lu², Hua Zhang², Jianping Sun², Jinguang Cheng², Chengmin Shen², Xiao Lin³, Binghai Yan⁴, Xingjiang Zhou², Ziqiang Wang⁵, Stephen J Pennycook⁶, Hui Chen⁷, Xiaoli Dong⁸, Wu Zhou⁹, Hong-Jun Gao¹⁰

Affiliations

¹ Beijing National Center 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; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.
² Beijing National Center 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.
³ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
⁴ Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
⁵ Department of Physics, Boston College, Chestnut Hill, MA 02467, USA.
⁶ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China; Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁷ Beijing National Center 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; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China. Electronic address: hchenn04@iphy.ac.cn.
⁸ Beijing National Center 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. Electronic address: dong@iphy.ac.cn.
⁹ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China. Electronic address: wuzhou@ucas.ac.cn.
¹⁰ Beijing National Center 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; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China. Electronic address: hjgao@iphy.ac.cn.

PMID: 36545993
DOI: 10.1016/j.scib.2022.10.015

Abstract

The vanadium-based kagome superconductor CsV₃Sb₅ has attracted tremendous attention due to its unexcepted anomalous Hall effect (AHE), charge density waves (CDWs), nematicity, and a pseudogap pair density wave (PDW) coexisting with unconventional strong-coupling superconductivity. The origins of CDWs, unconventional superconductivity, and their correlation with different electronic states in this kagome system are of great significance, but so far, are still under debate. Chemical doping in the kagome layer provides one of the most direct ways to reveal the intrinsic physics, but remains unexplored. Here, we report, for the first time, the synthesis of Ti-substituted CsV₃Sb₅ single crystals and its rich phase diagram mapping the evolution of intertwining electronic states. The Ti atoms directly substitute for V in the kagome layers. CsV_3-_xTi_xSb₅ shows two distinct superconductivity phases upon substitution. The Ti slightly-substituted phase displays an unconventional V-shaped superconductivity gap, coexisting with weakening CDW, PDW, AHE, and nematicity. The Ti highly-substituted phase has a U-shaped superconductivity gap concomitant with a short-range rotation symmetry breaking CDW, while long-range CDW, twofold symmetry of in-plane resistivity, AHE, and PDW are absent. Furthermore, we also demonstrate the chemical substitution of V atoms with other elements such as Cr and Nb, showing a different modulation on the superconductivity phases and CDWs. These findings open up a way to synthesise a new family of doped CsV₃Sb₅ materials, and further represent a new platform for tuning the different correlated electronic states and superconducting pairing in kagome superconductors.

Keywords: Charge density waves; Chemical doping; Competing orders; Kagome superconductor; Nematicity.