2019/09/30 by Bryan T. Fichera, Anshul Kogar, Linda Ye +4 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.101.241106
published as Phys. Rev. B 101, 241106 (2020) · 13 pages, 10 figures. Edited (v2) to include Bilal Gökce in the authors list who was mistakenly excluded. Edited again (v3) to incorporate modifications recommended by referees. Replaced (v4) with version published in Physical Review B
arxiv created 2020/06/10 · arxiv updated 2020/07/01
The notion of spontaneous symmetry breaking has been used to describe phase transitions in a variety of physical systems. In crystalline solids, the breaking of certain symmetries, such as mirror symmetry, is difficult to detect unambiguously. Using 1T-TaS2, we demonstrate here that rotational-anisotropy second harmonic generation (RA-SHG) is not only a sensitive technique for the detection of broken mirror symmetry, but also that it can differentiate between mirror symmetry-broken structures of opposite planar chirality. We also show that our analysis is applicable to a wide class of different materials with mirror symmetry-breaking transitions. Lastly, we find evidence for bulk mirror symmetry-breaking in the incommensurate charge density wave phase of 1T-TaS2. Our results pave the way for RA-SHG to probe candidate materials where broken mirror symmetry may play a pivotal role.