MBE Synthesis and Characterization of Intrinsic Magnetic Topological Insulator MnBi<sub>2</sub>Se<sub>4</sub>
ORAL
Abstract
Intrinsic magnetic topological insulators are stoichiometric materials with both magnetic ordering and topological electronic states. Due to its inherent magnetism, this class of materials processes rich topological quantum phases that induced by symmetry breaking, while maintaining good crystallinity and high purity of the material. We report the MBE synthesis and characterization of an intrinsic magnetic topological insulator MnBi2Se4. The MnBi2Se4 thin films are deposited with alternating layer growth of Bi2Se3 and a-MnSe(111). The high quality of the material is shown with cross-sectional TEM. Dirac surface state is demonstrated with angle-resolved photoemission spectroscopy above its magnetic ordering temperature. SQUID magnetometry measurement on films with different thicknesses shows layered-antiferromagnetic ordering in this material. Low-field SQUID measurement also shows a hysteresis loop, with magnetic moments preferred to stay within the lattice plane. The ferromagnetic signal is attributed to uncompensated magnetic moments at the surface. Its magnetic characterization is also confirmed with XMCD measurement. Furthermore, magnetometry measurement also shows that the magnetic ordering in MnBi2Se4 persists down to the monolayer limit.
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Presenters
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Tiancong Zhu
- University of California, Berkeley
- Department of Physics, University of California, Berkeley
- Ohio State Univ - Columbus