title: Atomistic origin of an ordered superstructure induced superconductivity in layered chalcogenides.
abstract: Interplay among various collective electronic states such as charge density wave and superconductivity is of tremendous significance in low-dimensional electron systems. However, the atomistic and physical nature of the electronic structures underlying the interplay of exotic states, which is critical to clarifying its effect on remarkable properties of the electron systems, remains elusive, limiting our understanding of the superconducting mechanism. Here, we show evidence that an ordering of selenium and sulphur atoms surrounding tantalum within star-of-David clusters can boost superconductivity in a layered chalcogenide 1T-TaS2-xSex, which undergoes a superconducting transition in the nearly commensurate charge density wave phase. Advanced electron microscopy investigations reveal that such an ordered superstructure forms only in the x area, where the superconductivity manifests, and is destructible to the occurrence of the Mott metal-insulator transition. The present findings provide a novel dimension in understanding the relationship between lattice and electronic degrees of freedom.
authors.affiliation: National Institute for Materials Science (NIMS), International Center for Materials Nanoarchitechtonics (MANA), Namiki 1-1, Tsukuba 305-0044, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ang
authors.affiliation: Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Z C
authors.initials: ZC
authors.lastname: Wang
authors.affiliation: Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: C L
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China.
authors.forename: J
authors.initials: J
authors.lastname: Tang
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China.
authors.forename: N
authors.initials: N
authors.lastname: Liu
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: W J
authors.initials: WJ
authors.lastname: Lu
authors.affiliation: 1] Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China [2] High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Y P
authors.initials: YP
authors.lastname: Sun
authors.affiliation: National Institute for Materials Science (NIMS), International Center for Materials Nanoarchitechtonics (MANA), Namiki 1-1, Tsukuba 305-0044, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mori
authors.affiliation: 1] Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan [2] Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan [3] Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta, Nagoya 456-8587, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ikuhara