The layered transition metal dichalcogenides(TMDs)have raised considerable interest in the past decades for both fundamental physics and low-dimensional nanodevice applications.Recently,intriguing phenomena of Ising s...The layered transition metal dichalcogenides(TMDs)have raised considerable interest in the past decades for both fundamental physics and low-dimensional nanodevice applications.Recently,intriguing phenomena of Ising superconductivity and quantum metallic state have been reported in two-dimensional(2D)4Ha-TaSe2 nanodevices.Here,we report the magnetic field induced superconductor–metal transition(SMT)in mechanical exfoliated 4Ha-TaSe2 nanodevices with thickness down to 2.5 nm.We observe the quantum Griffiths singularity(QGS)of SMT in thin 4Ha-TaSe2 nanodevices by performing ultralow temperature transport measurements and activated scaling analysis.With increasing the thickness of TaSe2 nanodevice to 10.6 nm,the signature of magnetoresistance crossing region can hardly be detected,revealing the thickness dependence of SMT.In this procedure,the disorder strength plays a dominant role.This work enriches the platform for studying QGS and may stimulate further investigations on the correlation between different novel quantum phenomena in the same 2D superconducting system.展开更多
The authors prove that the total descendant potential functions of the theory of Fan-Jarvis-Ruan-Witten for D4 with symmetry group J and for D4T with symmetry group Gmax, respectively, are both tau-functions of the D4...The authors prove that the total descendant potential functions of the theory of Fan-Jarvis-Ruan-Witten for D4 with symmetry group J and for D4T with symmetry group Gmax, respectively, are both tau-functions of the D4 Kac-Wakimoto/Drinfeld-Sokolov hierarchy. This completes the proof, begun in the article by Fan-Jarvis-Ruan（2013）, of the Witten Integrable Hierarchies Conjecture for all simple（ADE） singularities.展开更多
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 wh...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 b - 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 tc⊥1~ 8 nm and then from multiple quantum criticality to single criticality at tc⊥2~ 16 nm. Moreover, the superconducting-metal transition is observed for the first time under in-plane magnetic fields and the universality class is changed at tc‖~ 8 nm. 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.展开更多
基金the National Natural Science Foundation of China(Nos.11888101,11974430,and 12174442)the National Key R&D Program of China(Nos.2018YFA0305600 and 2022YFA1403103)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB28000000)the Innovation Program for Quantum Science and Technology(No.2021ZD0302400)Young Elite Scientists Sponsorship Program by BAST(No.BYESS2023452)the Fundamental Research Funds for the Central Universities,and the Research Funds of Renmin University of China(No.22XNKJ20).
文摘The layered transition metal dichalcogenides(TMDs)have raised considerable interest in the past decades for both fundamental physics and low-dimensional nanodevice applications.Recently,intriguing phenomena of Ising superconductivity and quantum metallic state have been reported in two-dimensional(2D)4Ha-TaSe2 nanodevices.Here,we report the magnetic field induced superconductor–metal transition(SMT)in mechanical exfoliated 4Ha-TaSe2 nanodevices with thickness down to 2.5 nm.We observe the quantum Griffiths singularity(QGS)of SMT in thin 4Ha-TaSe2 nanodevices by performing ultralow temperature transport measurements and activated scaling analysis.With increasing the thickness of TaSe2 nanodevice to 10.6 nm,the signature of magnetoresistance crossing region can hardly be detected,revealing the thickness dependence of SMT.In this procedure,the disorder strength plays a dominant role.This work enriches the platform for studying QGS and may stimulate further investigations on the correlation between different novel quantum phenomena in the same 2D superconducting system.
基金supported by the National Natural Science Foundation of China(Nos.1132510111271028)+1 种基金the National Security Agency of USA(No.H98230-10-1-0181)the Doctoral Fund of the Ministry of Education of China(No.20120001110060)
文摘The authors prove that the total descendant potential functions of the theory of Fan-Jarvis-Ruan-Witten for D4 with symmetry group J and for D4T with symmetry group Gmax, respectively, are both tau-functions of the D4 Kac-Wakimoto/Drinfeld-Sokolov hierarchy. This completes the proof, begun in the article by Fan-Jarvis-Ruan（2013）, of the Witten Integrable Hierarchies Conjecture for all simple（ADE） singularities.
基金supported by the National Key Research and Development Program of China (2017YFA0303302, 2018YFA030560 and 2017YFA0303301)the National Natural Science Foundation of China (11934005, 11474058, 11874116, 11674028 and 11534001)+9 种基金the National Natural Science Foundation of China (U1932154)the Science and Technology Commission of Shanghai (19511120500)the Shanghai Municipal Science and Technology Major Project (2019SHZDZX01)the Program of Shanghai Academic/Technology Research Leader (20XD1400200)supported by National Science Foundation Cooperative Agreement No. DMR-1644779, No. DMR-1157490the State of Floridasupport from China Postdoctoral Innovative Talents Support Program (BX20190085)China Postdoctoral Science Foundation (2019 M661331)supported by the Scientific Instrument Developing Project of CAS (YJKYYQ20180059)the Youth Innovation Promotion Association CAS (2018486)。
文摘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 b - 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 tc⊥1~ 8 nm and then from multiple quantum criticality to single criticality at tc⊥2~ 16 nm. Moreover, the superconducting-metal transition is observed for the first time under in-plane magnetic fields and the universality class is changed at tc‖~ 8 nm. 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.
