Condensed-Matter Physics & Materials Science Seminar

Weyl semimetals are new states of matter which feature novel Fermi arcs and exotic transport phenomena. Based on first-principles calculations, we report that the HgTe-class materials [1] as well as four chalcopyrites [2] are ideal Weyl semimetals, having largely separated Weyl points and uncovered Fermi arcs that are amenable to experimental detections. We also construct a minimal effective model to capture the low-energy physics of this class of Weyl semimetals. Our discovery is a major step toward a perfect playground of intriguing Weyl semimetals and potential applications for low-power and high-speed electronics. Besides the ideal Weyl semimetals, I will talk about Non-Hermitian nodal-line semimetals with an anomalous bulk-boundary correspondence [3]. I will also present recent results of saddle surface in topological materials and a new method to construct a simplified tight-binding model based on group theory analysis. [1] JR et al., Nature communications 7, 11136 (2016). [2] JR et al., PRL 116, 226801 (2016). [3] H. Wang, JR, and H. Zhang, PRB 99, 075130 (2019).