2020/01/13 by M. Otteneder, Maximilian Otteneder, D. Sacré +22
Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Cyclotron resonance #Dispersion (optics) #Excited state #Impurity #Magnetic field #Metamaterials and Metasurfaces Applications #Photoionization #Surface states #Terahertz radiation #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1002/pssb.202000023
13 pages, 13 figures
arxiv created 2020/01/13 · openalex created_date 2020/01/23 · openalex publication_date 2020/04/18 · arxiv updated 2021/02/03 · openalex updated_date 2026/08/05
Herein, studies of the cyclotron resonance (CR) in thick films with different cadmium contents corresponding to materials with and without band inversion, as well as critical content corresponding to an almost linear energy dispersion are presented. The results demonstrate that the formation of 2D topological surface states requires sharp interfaces between layers with and without band inversion, in which case the corresponding CR is clearly observed for the out‐of‐plane orientation of magnetic field but does not show up for an in‐plane orientation. In contrast, all samples having more conventional technological design with smooth interfaces (i.e., containing regions of with gradually changing Cd content x ) show equally pronounced CR in both in‐plane and out‐of‐plane magnetic field revealing that CR is excited in effectively 3D states. Modeling of the surface states for different film designs supports main observations. In all samples, additional broad helicity‐independent resonances are observed, which are attributed to photoionization and magnetic freeze‐out of impurity states.