[Jiho Jang and Prof. Hongki Min] Optical Transitions of a Single Nodal Ring in SrAs3: Radially and Axially Resolved Characterization (Published in Physical Review Letters)
SrAs3 is a unique nodal-line semimetal that contains only a single nodal ring in the Brillouin zone, uninterrupted by any trivial bands near the Fermi energy. We performed axis-resolved optical reflection measurements on SrAs3 and observed that the optical conductivity exhibits flat absorption up to 129 meV in both the radial and axial directions, confirming the robustness of the universal power-law behavior of the nodal ring. The axis-resolved optical conductivity, in combination with theoretical calculations, further reveals fundamental properties beyond the flat absorption, including the overlap energy of the topological bands, the spin-orbit coupling gap along the nodal ring, and the geometric properties of the nodal ring such as the average ring radius, ring ellipticity, and velocity anisotropy. In addition, our temperature-dependent measurements revealed a spectral weight transfer between intraband and interband transitions, indicating a possible violation of the optical sum rule within the measured energy range.
This work is done in collaboration with Mr. Jiwon Jeon and Prof. Eunjip Choi at University of Seoul, along with other collaborators.
Authors: Jiwon Jeon*, Jiho Jang*, Hoil Kim, Taesu Park, Dongwook Kim, Soonjae Moon, Jun Sung Kim, Ji Hoon Shim, Hongki Min**, and Eunjip Choi**
(*co-first authors, **co-corresponding authors)
Title: Optical Transitions of a Single Nodal Ring in SrAs3: Radially and Axially Resolved Characterization
Journal: Phys. Rev. Lett. 131, 236903 (2023)
Publication date: 6 December 2023