Bulletin of the American Physical Society
APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session S04: Dynamics of Chiral Spin Textures in Topological and Magnetic MaterialsInvited
|
Hide Abstracts |
Sponsoring Units: DCMP DMP GMAG Chair: Clifford Bowers, University of Florida - Gainesville Room: LACC 151 |
Thursday, March 8, 2018 11:15AM - 11:51AM |
S04.00001: A Fermi liquid with spin-orbit coupling Invited Speaker: Dmitrii Maslov In a series of papers [1-4], we have constructed a theory of a Fermi liquid (FL) with spin-orbit coupling. The main prediction of this theory is a new type of collective modes: chiral spin waves, which are oscillations of magnetization in a time-reversal--invariant system. The focus of this talk will be on the interpretation of recent Raman experiments, on a CdMnTe quantum well [5] and on the surface state of a topological insulator Bi2Se3 [6], which show features consistent with chiral spin waves. |
Thursday, March 8, 2018 11:51AM - 12:27PM |
S04.00002: Spin-orbit twisted spin waves in magnetic quantum wells Invited Speaker: Florent Perez Spin-wave based transistors are an appealing alternative to the traditional charge-based transistor, since spin waves carry information with reduced dissipation compared to charge currents. However, one still has to develop efficient methods for controlling the spin waves with low energy cost, a condition not satisfied by the manipulation with magnetic fields. |
Thursday, March 8, 2018 12:27PM - 1:03PM |
S04.00003: Chiral Spin Mode on the Surface of a Topological Insulator Invited Speaker: Girsh Blumberg In nonmagnetic materials where inversion symmetry is broken but time-reversal invariance is intact, strong spin-orbit coupling (SOC) may play the role of an effective magnetic field, which locks electron spins and momenta into textures. This phenomenon is encountered in 3D topological insulators (TIs), which harbor topologically protected surface states. An essential aspect of this physics is an interplay between the Coulomb interaction and SOC, which gives rise to a new type of collective spin excitations – chiral spin waves [1]. In the long wavelength limit, these modes are decoupled from the charge channel and thus are distinct from spin plasmons, Dirac plasmons, and surface plasmons in TIs. |
Thursday, March 8, 2018 1:03PM - 1:39PM |
S04.00004: Helical Fermi liquids and their breakdown Invited Speaker: Joseph Maciejko The surface of 3D strong topological insulators such as Bi2Se3 harbors a new gapless state of matter, the 2D helical Fermi liquid, where a novel phenomenology distinct from that of the conventional 2D Fermi liquid arises out of the interplay of Coulomb interactions and a spin-momentum locked Fermi surface, the latter originating from strong spin-orbit coupling in the topological bandstructure. Aspects of this predicted phenomenology, such as novel spin-orbit coupled collective modes, have recently been observed experimentally. In this talk I will present an extension of Landau’s phenomenological Fermi liquid theory to the case of the helical Fermi liquid, and derive from it the renormalization of equilibrium properties, criteria for Fermi surface instabilities, and collective mode dispersions. I will then discuss the quadrupolar Pomeranchuk instability in greater detail and its observable signatures, such as anisotropies in charge and spin response functions, the partial breakdown of spin-momentum locking, collective modes and induced spin fluctuations, and non-Fermi liquid behavior. |
Thursday, March 8, 2018 1:39PM - 2:15PM |
S04.00005: Quantized Electro-dynamical Responses In Topological Materials Invited Speaker: Liang Wu The last decade has witnessed an explosion of research investigating the role of topology in band-structure, as characterized for example by the Berry curvature in momentum space in the electronic response of topological insulators (TIs) to Weyl semimetals (WSMs). In this talk I hope to convince you that optical probes of solids give unique insight into these topological states of matter. First, I will discuss how we can probe the special low-energy electrodynamics of 3D TI thin films of Bi2Se3 using time-domain THz spectroscopy. I will then discuss our work following the evolution of the response as a function of magnetic field from the semi-classical transport regime to the quantum regime. In the later case, although DC transport is still semi-classical, we find evidence for Faraday and Kerr rotation angles quantized in units of the fine structure constant. This is consistent with the long-sought axion electrodynamics and the topological magneto-electric effect of 3D TIs. Among other aspects this give a purely solid-state measure of the fine structure constant as a topological invariant. Finally, I will also discuss how optics can observe quantized Hall conductance without involving the edge states. If time permits, I would briefly discuss a new quantized effect in Weyl semimetals. |
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