2023/05/04(Thu)
10:30 -12:00
五樓第一會議室 5F, 1st Meeting Room
視訊演講 Video Seminar [ Meeting Link / ID: 2512 474 1286 / Password: 123456 ]
- 實體與視訊演講同時進行。
- Both physical seminar and virtual seminar are available.
Title
Ab-initio study of nonlinear optics of chiral Weyl semimetals XY (X=Co, Rh; Y=Si,Ge) and ideal nodal-line semimetals CaAg-Pnictides (P, As)
Speaker
江明寯先生 ([1] RIKEN CEMS, Japan [2] National Taiwan University) Mr. Ming-Chun Jiang ([1] RIKEN CEMS, Japan [2] National Taiwan University)Abstract
Extending from linear optics and occurring only in noncentrosymmetric materials, the second-order nonlinear optical (NLO) responses have recently gained attention. Also, the relation between quantum geometry and two of the NLO effects, which are the second harmonic generation (SHG) [1] and bulk photovoltaic effects (BPVE) [2], has been established. Along with the divergence behavior of the NLO effect in topological crossings in semimetals, we would expect peculiar NLO effects among topological semimetals [2,3]. In this talk, I will present the results of our ab-initio calculations of NLO for firstly, chiral Weyl semimetals, XY (X=Co, Rh; Y=Si, Ge) with spin-1 and spin-3/2 chiral fermions [4]. We observe divergent SHG peaks in the low-frequency region as well as possible quantized BPVE signals. Secondly, we investigate CaAg-Pnictides (P, As) that obtain an ideal nodal line. We report on the significant BPVE signals at visible light regions as well as the divergent profile for NLO of a single nodal line.
[1] Pankaj Bhalla, Kamal Das, Dimitrie Culcer, and Amit Agarwal, Phys. Rev. Lett. 129, 227401 (2022)
[2] Junyeong Ahn, Guang-Yu Guo, and Naoto Nagaosa, Phys. Rev. X 10, 041041 (2020)
[3] Omid Tavakol and Yong Baek Kim, Phys. Rev. B 107, 035114 (2023)
[4] Ting-Yun Hsieh, Babu Baijnath Prasad, and Guang-Yu Guo, Phys. Rev. B 106, 165102 (2022)
Language
演講語言 (Language): in English