Temperature and Magnetic Field Dependence of the Raman Spectra of TaSe<sub>2</sub>

POSTER

Abstract

A layered, transition-metal dichalcogenide (TMD), TaSe2 continues to attract interest for advanced device applications. In bulk form, metallic TaSe2 exhibits transitions between commensurate and incommensurate charge-density wave (CDW) phases. In the present work, we extend our opto-thermal Raman measurements1 on MoS2 to include bulk TaSe2 in both 1T and 2H crystallographic phases. A novel, magneto-Raman microscope system affords measurement of low-frequency (down to 10 cm-1) vibrational modes as a function of both temperature (100 to 400)K and magnetic field (0 to 9)T. The dependence of the observed Raman-active phonons on temperature and magnetic field will be presented and compared with earlier results on MoS2. Specifically, we observe the appearance of low-frequency, zone-folded modes in the CDW state, which soften with temperature similar to the higher frequency, in-plane E2g mode. Additionally, we compare the measured magneto-Raman results to calculations using ab initio, density functional theory.

1 R. Yan, J. R. Simpson, et al., ACS Nano 8, 986 (2014).

*We acknowledge support from NSF grant DMR# 1709781 and the Jess and Mildred Fisher College of Science & Mathematics at Towson University.

Presenters

  • Hamna Ali

    • Physics, Astronomy, and GeoSciences, Towson University

Authors

  • Hamna Ali

    • Physics, Astronomy, and GeoSciences, Towson University

  • Sugata Chowdhury

    • National Institute of Standards and Technology

  • Heather Hill

    • Engineering Physics, National Institute of Standards and Technology
    • National Institute of Standards and Technology
    • Physical Measurements Laboratory, National Institute of Standards and Technology
    • Physical Measurment Division, NIST
    • NIST -Natl Inst of Stds & Tech
    • NIST - National Institute of Standards and Technology

  • Angela Hight Walker

    • Engineering Physics, National Institute of Standards and Technology
    • National Institute of Standards and Technology
    • NIST - Natl Inst of Stds & Tech
    • Physical Measurements Laboratory, National Institute of Standards and Technology
    • Physical Measurment Division, NIST
    • NIST -Natl Inst of Stds & Tech
    • Physical Measurement Laboratory, National Institute of Standards and Technology
    • NIST - National Institute of Standards and Technology
    • National Institute of Standards and Technology (NIST)
    • National Institute of Standards & Technology

  • Jeffrey Simpson

    • Engineering Physics, National Institute of Standards and Technology
    • Physics, Towson University
    • Physics, Astronomy, and GeoSciences, Towson University
    • Towson University
    • Department of Physics, Astronomy, and Geosciences, Towson University
    • Physics, Astronomy, and Geosciences, Towson Univ and NIST