Abstract
ReS2 is a group-VII chalcogenide with a crystal structure that has inversion symmetry only. Due to the low symmetry, it has in-plane anisotropy, and the two vertical orientations are not equivalent. The in-plane anisotropy leads to optical birefringence that can be observed by using polarized optical microscopy. We found ReS2 crystals with domains of inequivalent vertical orientations but with the same Re-chain directions. Polarized Raman spectroscopy was used to determine the vertical orientations and the b-axis (Re-chain) directions of the domains, and high-resolution scanning transmission electron microscopy measurements confirmed that the Re-chain directions of the two types of the neighboring domains are exactly parallel. From polarized optical reflectivity measurements of the two types of domains, we found that the optical slow axis is not along the b-axis as previously believed but is tilted by ∼2.4° from the b-axis of the crystal. This offset makes the two neighboring domains with parallel Re-chains optically inequivalent and enables one to observe optical contrast between the two types of domains in polarized optical microscopy. We propose a quick and easy method to determine the crystallographic orientations of such domains by using polarized optical microscopy only.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.