Features of Charge Density Wave Energy Gap and Electronic Dispersion of $2H-\textrm{TaS}_2$ and Other Layered Transition Metal Dichalcogenides.

ORAL

Abstract

We present Angle Resolved Photoemission Spectroscopy (ARPES) study of $2H-\textrm{TaS}_2$, a canonical incommensurate Charge Density Wave (CDW) material, and compare to similar layered transition metal dichalcogenides such as $2H-\textrm{NbSe}_2$. Similarities were observed in the preferential appearance of CDW energy gap in the vicinity of some specific high symmetry points on the Fermi surface, the particle-hole asymmetry of this gap and the existence of the pseudogap behavior above CDW transition temperature. However, in contrast to $2H-\textrm{NbSe}_2$, where the gap opens up only in specific momentum locations in the vicinity of high symmetry points, we observed a non-zero gap for all momentum locations for the case of $2H-\textrm{TaS}_2$. Since the conventional Fermi surface nesting model was unable to explain these similarities and differences, we use a tight binding model with emphasis on orbital selectivity and strong electron-phonon coupling. Further analysis of the electronic dispersion showed pronounced many body renormalization in the system and revealed the phononic mechanism behind momentum and temperature dependent features of the band structure. We suggest that this model can be generalized for a broader class of incommensurate charge density wave materials.

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Authors

  • Kapila Wijayaratne

    Univ of Virginia

  • S.S. Gupta

    Department of Applied Mathematics & Sciences, Khalifa University, Abu Dhabi 127788, UAE, Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA, Indian Institute of Technology Ropar, Nangal Road, Rupnagar (Ropar), Punjab 140 001, India, The Institute for Nuclear Research, Moscow, Davidson Coll, Western kentucky University, Bowling Green, KY 42101, Naval Postgraduate School, Austin Peay State University, Univ of Tennessee, Knoxville, University of Nebraska, Rajarata University of Sri Lanka, University of West Georgia, Department of Physics, University of Alabama at Birmingham, Center for High Pressure Science and Technology Advanced Research, Northwestern Univ, Univ of Virginia, Western Kentucky University, Physics Dept. Bowling Green, KY, Department of Physics, The University of Texas-Rio Grande Valley, TX 78539, Western Kentucky University, Bowling Green, KY 42101, Western Kentucky University, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom, Austin Peay State Univ, University of Pardubice, Clemson University, Appalachian State Univ, Department of Physics, University of West Georgia, Department of Geosciences, University of West Georgia, Department of Physics and Astronomy, Georgia State University, Francis Marion University, The Pennsylvania State University, Auburn University, Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana, Department of Physics, Brigham Young University-Idaho, Rexburg, Idaho, Department of Physics,North Carolina State University, William Mong Institute of Nano Science and Technology, MSTD, Oak Ridge National Laboratory, Department of Physics and Astronomy, Vanderbilt University, Univ of Bristol, University of Alabama in Birmingham, Georgia Institute of Technology, Sandia National Laboratories, University of South Florida

  • S.S. Gupta

    Department of Applied Mathematics & Sciences, Khalifa University, Abu Dhabi 127788, UAE, Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA, Indian Institute of Technology Ropar, Nangal Road, Rupnagar (Ropar), Punjab 140 001, India, The Institute for Nuclear Research, Moscow, Davidson Coll, Western kentucky University, Bowling Green, KY 42101, Naval Postgraduate School, Austin Peay State University, Univ of Tennessee, Knoxville, University of Nebraska, Rajarata University of Sri Lanka, University of West Georgia, Department of Physics, University of Alabama at Birmingham, Center for High Pressure Science and Technology Advanced Research, Northwestern Univ, Univ of Virginia, Western Kentucky University, Physics Dept. Bowling Green, KY, Department of Physics, The University of Texas-Rio Grande Valley, TX 78539, Western Kentucky University, Bowling Green, KY 42101, Western Kentucky University, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom, Austin Peay State Univ, University of Pardubice, Clemson University, Appalachian State Univ, Department of Physics, University of West Georgia, Department of Geosciences, University of West Georgia, Department of Physics and Astronomy, Georgia State University, Francis Marion University, The Pennsylvania State University, Auburn University, Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana, Department of Physics, Brigham Young University-Idaho, Rexburg, Idaho, Department of Physics,North Carolina State University, William Mong Institute of Nano Science and Technology, MSTD, Oak Ridge National Laboratory, Department of Physics and Astronomy, Vanderbilt University, Univ of Bristol, University of Alabama in Birmingham, Georgia Institute of Technology, Sandia National Laboratories, University of South Florida

  • S.S. Gupta

    Department of Applied Mathematics & Sciences, Khalifa University, Abu Dhabi 127788, UAE, Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA, Indian Institute of Technology Ropar, Nangal Road, Rupnagar (Ropar), Punjab 140 001, India, The Institute for Nuclear Research, Moscow, Davidson Coll, Western kentucky University, Bowling Green, KY 42101, Naval Postgraduate School, Austin Peay State University, Univ of Tennessee, Knoxville, University of Nebraska, Rajarata University of Sri Lanka, University of West Georgia, Department of Physics, University of Alabama at Birmingham, Center for High Pressure Science and Technology Advanced Research, Northwestern Univ, Univ of Virginia, Western Kentucky University, Physics Dept. Bowling Green, KY, Department of Physics, The University of Texas-Rio Grande Valley, TX 78539, Western Kentucky University, Bowling Green, KY 42101, Western Kentucky University, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom, Austin Peay State Univ, University of Pardubice, Clemson University, Appalachian State Univ, Department of Physics, University of West Georgia, Department of Geosciences, University of West Georgia, Department of Physics and Astronomy, Georgia State University, Francis Marion University, The Pennsylvania State University, Auburn University, Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana, Department of Physics, Brigham Young University-Idaho, Rexburg, Idaho, Department of Physics,North Carolina State University, William Mong Institute of Nano Science and Technology, MSTD, Oak Ridge National Laboratory, Department of Physics and Astronomy, Vanderbilt University, Univ of Bristol, University of Alabama in Birmingham, Georgia Institute of Technology, Sandia National Laboratories, University of South Florida

  • U. Chatterjee

    Univ of Virginia