Engineering magnetic topological insulator-topological insulator superlattices as a novel topological quantum materials
Abstract
Following the discovery of the quantum anomalous Hall effect and the emergence of novel quantum phenomena, magnetic topological insulators have recently received considerable attention. In this proposal, we aim to advance the MTI research field by creating MTI-TI multilayered superlattices. We will fabricate multilayer MTI-TI films with good stoichiometric precision utilizing state-of-art molecular beam epitaxy growth. The film morphology, and the atomic and electronic structure associated with pristine surfaces, and point defects will be characterized in-situ by scanning tunneling microscopy-spectroscopy down to the atomic scale. Moreover, the spin-textures of this new MTI platform will be investigated using spin-polarized STM-S with the aim of direct visualization of the intrinsic antiferromagnetic spin structures in real-space. In addition, the outstanding axial spin-flop transitions can also be accessed by applying external out-of-plane magnetic fields, leading to drastic changes in magnetic spin contrasts. On the theoretical side, we will continue to develop and apply the Coupled Dirac Cone Model to capture more realistic details, and to describe lateral interfaces between topological phases with different Chern numbers. We will also use density functional theory to predict the spin-resolved spectral features to cross-corroborate with the SP-STM investigation. The combination of DFT and the CDCM will be able to realistically take into account disorder, external magnetic field, electrical gating, and other relevant factors in the experimental setup. We will take this advantage of the model to map out the phase diagram of possible Weyl semimetal and various QAH states in our experimentally accessible parameter space.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 10, 2022
- Source ID
- FA23862114061XX53
Entities
People
- Chih-Kang Shih
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Texas at Austin