General and specific features of the charge density waves in transition metal dichalcogenides

ORAL

Abstract

We report a series of elaborate Angle-Resolved Photoemission Spectroscopy (ARPES) studies on the charge density wave (CDW) phase in transition metal dichalcogenides (TMD) 2H-TaS2, TaSe2 and NbSe2, analyzed above/ below the CDW transition temperature (TCDW). Generally; i) On Fermi surface, CDW energy gap appears only in the vicinity of some symmetry points, while other momentum points are ungapped. ii) Gap is asymmetric in particles and holes. iii) Gap existed above TCDW, beyond the CDW phase, (pseudogap). iv) Conventional Fermi surface nesting model is incapable of describing the CDWs in TMDs. v) phonon related band renormalizations were observed In 2H-TaS. Compound-specific features, due to different orbital orientations were; i) Size variation of some Fermi pockets are related to TCDW while other pockets were similar among compounds. ii) About a given symmetry point, in 2H-NbSe2 the gap size varied upon momentum in contrast to 2H-TaS2, where this variation was insignificant. A tight binding model that includes orbital selectivity and electron-phonon coupling can explain both general and specific features and might be extendable to a broad set of two-dimensional materials with CDW order, including cuprates.

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Presenters

  • Kapila Wijayaratne

    Department of Physics, University of Virginia

Authors

  • Kapila Wijayaratne

    Department of Physics, University of Virginia

  • Junjing Zhao

    Department of Physics, University of Virginia, Physics, University of Virginia

  • Christos Malliakas

    Department of Chemistry, Northwestern University, Northwestern University

  • Duck Young Chung

    Materials Science Division, Argonne National Laboratory, Materials Science Division, Argonne National Lab, Argonne National Laboratory

  • Genda Gu

    Brookhaven National Laboratory, Brookhaven National Lab, Department of Condensed Matter Physics and Materials Science, Brookhaven, Brookhaven National Laboratory, Upton, New York 11973-5000, USA., Cond. Matt. Physics and Material Science, Brookhaven Natl Lab, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Condensed Matter Physics & Materials Science Department, Brookhaven National Laboratory, Brookhaven National Labs, Long Island, NY, USA, 11973, Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Condensed Matter Physics, Brookhaven National Laboratory, Brookhaven National Laboratories, Chinese Academy of Sciences, Condensed Matter Physics & Materials Science, Brookhaven National Lab, Brookhaven Natl Lab

  • Mercouri Kanatzidis

    Department of Chemistry, Northwestern University, Chemistry, Northwestern University, Chemistry, Northwestern University, Evanston, IL 60208, Northwestern University, Materials Science Division, Argonne National Laboratory, Argonne National Laboratory

  • Jasper Van Wezel

    Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, University of Amsterdam, Institute of Theoretical Physics, University of Amsterdam

  • Utpal Chatterjee

    Department of Physics, University of Virginia, Physics, University of Virginia