doc. dr. sc. Zoran Rukelj, Prirodoslovno-matematički fakultet Sveučilište u Zagrebu, Fizički odsjek, Hrvatska će održati predavanje pod nazivom
“Magneto-optical transport properties of a semimetal with Mexican hat-like bands“
u utorak 26. ožujka 2024. godine na Prirodoslovno-matematičkom fakultetu Sveučilišta u Splitu, Ulica R. Boškovića 33, u dvorani B 3-37 s početkom u 10:00h.
Abstract: We study the single-particle, electronic transport, and optical properties of a gapped system described by a simple two-band Hamiltonian with Mexican hat-like valence bands. We analyze its properties in the three-dimensional (3D) and the two-dimensional (2D) case. The insulating phase changes into a metallic phase when the band gap is set to zero. The metallic phase in the 3D case is characterized by a nodal surface. This nodal surface is equivalent to a nodal ring in two dimensions. Within a simple theoretical framework, we calculate the density of states, the total and effective charge carrier concentration, the Hall concentration, and the Hall coefficient, for both 2D and 3D cases. The main result is that the three concentrations always differ from one another in the present model. These concentrations can then be used to resolve the nature of the electronic ground state. Similarly, the optical conductivity is calculated and discussed for the insulating phase. We show that there are no optical excitations in the nodal phase. Finally, we generalize the two-band model for 2D systems to include topological nontrivial cases and analyze the experimental predictions.
