Bulletin of the American Physical Society
Mid-Atlantic Section Fall Meeting 2020
Volume 65, Number 20
Friday–Sunday, December 4–6, 2020; Virtual
Session C05: Topological Materials II |
Hide Abstracts |
Chair: Yi Li, Johns Hopkins University |
Friday, December 4, 2020 4:30PM - 5:06PM |
C05.00001: Discovery of Topological Magnets in 2D and 3D Invited Speaker: M. Zahid Hasan In this talk I present our research on 2D and 3D topological magnets in novel topological, Weyl-Dirac and kagome materials. I start with a demonstration of Chern gap in topological magnets based on intrinsic topological insulators (https://arxiv.org/pdf/0812.2078.pdf (2008) leading to S.-Y. Xu et.al., ``Hedgehog spin texture and Berry's phase tuning in a magnetic topological insulator'' Nature Physics 8, 616 (2012)) then describe a set of ideas and experiments that led to the discovery of Weyl magnets (Belopolski et.al., ``Discovery of topological Weyl fermion lines and drumhead surface states in a room temperature magnet'' SCIENCE 365, 1278 (2019)) and demonstration that certain kagome magnets can be topologically non-trivial (Yin et.al., NATURE 562, 91 (2018)) which then led to a new class of Chern magnets (Yin et.al., ``Quantum-limit Chern topological magnetism in TbMn6Sn6'' NATURE 583, 533 (2020)) with gap larger than 30 meV (\textgreater 300K). Our unique approach regarding the magnetic bulk--boundary--Berry correspondence covering real space and momentum space demonstrates a proof-of-principle method for revealing or discovering new topological magnets. [Preview Abstract] |
Friday, December 4, 2020 5:06PM - 5:42PM |
C05.00002: Ten-years-journey: From classical to quantum regime of topological surface states Invited Speaker: Seongshik Oh Since the notion~of~topological~insulator (TI) was envisioned about a decade ago, topology has become a new paradigm in condensed matter physics. Realization~of~topology as a generic property~of~materials has led to numerous predictions~of classical and quantum topological effects. Although most of the classical topological effects, directly resulting from the presence of the spin-momentum-locked topological surface states, were experimentally confirmed soon after the discovery of TIs, topological quantum effects remained elusive. It turns out that defects, especially interfacial defects, have been the main culprit behind this impasse. With a series of interface engineering schemes, however, the density of these interface defects and the corresponding residual carrier densities have decreased by 300 times over the past ten years. Subsequently, a series of topological quantum effects such as quantized Faraday/Kerr rotations, quantum Hall effects, topological quantum phase transitions, zeroth Landau level physics etc. started to emerge. Here, I will overview this ten-years-of-journey toward the extreme quantum regime of topological surface states. [Preview Abstract] |
Friday, December 4, 2020 5:42PM - 6:18PM |
C05.00003: Neutron Investigations of the Antiferromagnet Topological Insulator, MnBi$_2$Te$_4$ Invited Speaker: William Ratcliff In this talk, I discuss our recent results on the first intrinsic antiferromagnetic topological insulator, MnBi$_2$Te$_4$. In this Van der Waals material, we can control the magnetic state through chemical substitution, as well as through the application of a magnetic field. These knobs allow us to effect the topology of the band structure and thus the transport. We apply a number of probes, including transport, susceptibility, neutron scattering, ARPES, and TEM to determine the physics of this exciting material [1,2]. "Spin Scattering and noncollinear spin-structure induced intrinsic anomalous Hall Effect in antiferromagnetic topological insulator MnnBi2Te4, Seng Huat Lee et al, Phys. Rev. Research 1, 012011 (2019) "Ferromagnetism in van der Walls compound MnSb1.8Bi.2Te4" Yangyang Chen et al, Phys. Rev. Matt. 4, 064411 (2020) [Preview Abstract] |
Friday, December 4, 2020 6:18PM - 6:30PM |
C05.00004: Floquet engineering of twisted double bilayer graphene Martin Rodriguez-vega, Michael Vogl, Greg Fiete Motivated by the recent experimental realization of twisted double bilayer graphene (TDBG) samples, we study, both analytically and numerically, the effects of circularly polarized light propagating in free space and confined in a waveguide on the band structure and topological properties of these systems. These two complementary Floquet protocols allow us to selectively tune different parameters of the system by varying the intensity and light frequency. Furthermore, we study the topological properties of the driven system in different settings, provide accurate effective Floquet Hamiltonians, and show that relatively strong drives can generate flat bands. Reference Phys. Rev. Research 2, 033494 (2020) [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700