Quantum Griffiths singularities in TiO superconducting thin films with insulating normal states

doi:10.1038/s41427-019-0181-3

	Quantum Griffiths singularities in TiO superconducting thin films with insulating normal states
	Zhang, Chao 1,2; Fan, Yunjie 1,2; Chen, Qiaoling 1,2; Wang, Tianyi 1,2,3; Liu, Xiang 1,2; Li, Qi 3; Yin, Yuewei 1,2; Li, Xiaoguang 1,2,4,5
刊名	NPG ASIA MATERIALS
	2019-12-20
卷号	11
ISSN号	1884-4049
DOI	10.1038/s41427-019-0181-3
通讯作者	Yin, Yuewei(yyw@ustc.edu.cn) ; Li, Xiaoguang(lixg@ustc.edu.cn)
英文摘要	A superconductor-metal transition (SMT) with an unconventional diverging dynamic critical exponent was recently discovered, and it drew tremendous attention because this signature of a quantum Griffiths singularity (QGS) was thought to be a common characteristic of low-disorder crystalline superconductors. However, because the QGS was observed only in limited materials with metallic normal states, the question of whether the QGS exists in other superconducting systems is still unanswered. In this paper, a superconductor-insulator transition (SIT) is observed in TiO thin films with insulating normal states, which offers a more universal platform for investigating the QGS. A thickness-tuned SIT is obtained when the magnetic field is zero. Importantly, a magnetic field-tuned SIT with a diverging dynamic critical exponent, which is direct evidence of a QGS, is observed in TiO thin films with different thicknesses. By constructing a comprehensive phase diagram, it is demonstrated that the critical magnetic field H-c tends to saturate as the temperature approaches 0 K, which is different from the upturn trend of H-c observed in SMT systems and probably due to the weaker Josephson coupling of the locally ordered superconducting islands (rare regions) in a weakly insulating normal state background. The results extend the QGS scenario from only SMT systems to SIT systems, and they provide vital evidence that QGSs are common in crystalline superconducting thin films, which has possible applications in quantum-computing devices.
资助项目	National Natural Science Foundation of China[51790491] ; National Natural Science Foundation of China[51622209] ; National Natural Science Foundation of China[21521001] ; National Key Research and Development Program of China[2016YFA0300103] ; National Key Research and Development Program of China[2015CB921201] ; United States Department of Energy[DE-FG02-08ER46531]
WOS关键词	TRANSITION ; TEMPERATURE ; DEPENDENCE ; SURFACE ; ONSET
WOS研究方向	Materials Science
语种	英语
出版者	NATURE PUBLISHING GROUP
WOS记录号	WOS:000517099900001
资助机构	National Natural Science Foundation of China ; National Key Research and Development Program of China ; United States Department of Energy
内容类型	期刊论文
源URL	[http://ir.hfcas.ac.cn:8080/handle/334002/103969]
专题	中国科学院合肥物质科学研究院
通讯作者	Yin, Yuewei; Li, Xiaoguang
作者单位	1.Univ Sci & Technol China, Dept Phys, Hefei Natl Lab Phys Sci Microscale, Hefei 230026, Peoples R China 2.Univ Sci & Technol China, Dept Phys, CAS Key Lab Strongly Coupled Quantum Matter Phys, Hefei 230026, Peoples R China 3.Penn State Univ, Dept Phys, 104 Davey Lab, University Pk, PA 16802 USA 4.Chinese Acad Sci, Inst Solid State Phys, Key Lab Mat Phys, Hefei 230031, Peoples R China 5.Collaborat Innovat Ctr Adv Microstruct, Nanjing 210093, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Chao,Fan, Yunjie,Chen, Qiaoling,et al. Quantum Griffiths singularities in TiO superconducting thin films with insulating normal states[J]. NPG ASIA MATERIALS,2019,11.
APA	Zhang, Chao.,Fan, Yunjie.,Chen, Qiaoling.,Wang, Tianyi.,Liu, Xiang.,...&Li, Xiaoguang.(2019).Quantum Griffiths singularities in TiO superconducting thin films with insulating normal states.NPG ASIA MATERIALS,11.
MLA	Zhang, Chao,et al."Quantum Griffiths singularities in TiO superconducting thin films with insulating normal states".NPG ASIA MATERIALS 11(2019).