Temperature and Magnetic Field Dependence of the Raman Spectra of TaSe2

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).

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