jp7b10263_si_001.pdf (1.17 MB)
Unusual Pressure Response of Vibrational Modes in Anisotropic TaS3
journal contribution
posted on 2017-11-22, 00:00 authored by Kedi Wu, Bin Chen, Hui Cai, Mark Blei, Juliana Bennett, Shengxue Yang, David Wright, Yuxia Shen, Sefaattin TongayWe
report on the unique vibrational properties of 2D anisotropic
orthorhombic tantalum trisulfide (o-TaS3) measured through angle-resolved Raman spectroscopy and high-pressure
diamond anvil cell studies. Our broad-spectrum Raman measurements
identify optical and low-frequency shear modes in pseudo-1D o-TaS3 for the first time, and introduce their polarization resolved
Raman responses to understand atomic vibrations for these modes. Results
show that, unlike other anisotropic systems, only the S∥ mode at 54 cm–1 can be utilized to identify the
crystalline orientation of TaS3. More notably, high-pressure
Raman measurements reveal previously unknown four distinct types of
responses to applied pressure, including positive, negative, and nonmonotonic
dω/dP behaviors which are found to be closely
linked to atomic vibrations for involving these modes. Our results
also reveal that the material approaches an isotropic limit under
applied pressure, evidenced by a significant reduction in the degree
of anisotropy. Overall, these findings significantly advance not only
our understanding of their fundamental properties of pseudo-1D materials
but also our interpretations of the vibrational characteristics that
offer valuable insights about thermal, electrical, and optical properties
of pseudo-1D material systems.