Observation of thickness-tuned universality class in superconducting β-W thin films

Ce Huang; Enze Zhang; Yong Zhang; Jinglei Zhang; Faxian Xiu; Haiwen Liu; Xiaoyi Xie; Linfeng Ai; Yunkun Yang; Minhao Zhao; Junjie Qi; Lun Li; Shanshan Liu; Zihan Li; Runze Zhan; Ya-Qing Bie; Xufeng Kou; Shaozhi Deng; X C Xie

doi:10.1016/j.scib.2021.05.023

Observation of thickness-tuned universality class in superconducting β-W thin films

Sci Bull (Beijing). 2021 Sep 30;66(18):1830-1838. doi: 10.1016/j.scib.2021.05.023. Epub 2021 May 29.

Authors

Ce Huang¹, Enze Zhang¹, Yong Zhang², Jinglei Zhang³, Faxian Xiu⁴, Haiwen Liu⁵, Xiaoyi Xie¹, Linfeng Ai¹, Yunkun Yang¹, Minhao Zhao¹, Junjie Qi⁶, Lun Li², Shanshan Liu¹, Zihan Li¹, Runze Zhan⁷, Ya-Qing Bie⁷, Xufeng Kou², Shaozhi Deng⁷, X C Xie⁸

Affiliations

¹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China.
² School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China.
³ Anhui Province Key Laboratory of Condensed Matter Physics at ExtremeConditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.
⁴ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China. Electronic address: Faxian@fudan.edu.cn.
⁵ Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China. Electronic address: Haiwen.liu@bnu.edu.cn.
⁶ Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
⁷ State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China.
⁸ Beijing Academy of Quantum Information Sciences, Beijing 100193, China; International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.

PMID: 36654392
DOI: 10.1016/j.scib.2021.05.023

Abstract

The interplay between quenched disorder and critical behavior in quantum phase transitions is conceptually fascinating and of fundamental importance for understanding phase transitions. However, it is still unclear whether or not the quenched disorder influences the universality class of quantum phase transitions. More crucially, the absence of superconducting-metal transitions under in-plane magnetic fields in 2D superconductors imposes constraints on the universality of quantum criticality. Here, we observe the thickness-tuned universality class of superconductor-metal transition by changing the disorder strength in β-W films with varying thickness. The finite-size scaling uncovers the switch of universality class: quantum Griffiths singularity to multiple quantum criticality at a critical thickness of t_c⊥1~8nm and then from multiple quantum criticality to single criticality at t_c⊥2~16nm. Moreover, the superconducting-metal transition is observed for the first time under in-plane magnetic fields and the universality class is changed at t_c‖~8nm. The observation of thickness-tuned universality class under both out-of-plane and in-plane magnetic fields provides broad information for the disorder effect on superconducting-metal transitions and quantum criticality.

Keywords: Quantum criticality; Quenched disorder; Universality class; quantum Griffiths singularity.