Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session T19: Strong Electronic Correlations in Topological Materials: Theory |
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Sponsoring Units: DCMP Chair: Zijia Cheng, Princeton University Room: Room 211 |
Thursday, March 9, 2023 11:30AM - 11:42AM |
T19.00001: Topological Quantum Chemistry for heavy fermion systems Mikel Iraola Iñurrieta, Roser Valenti, Maia Garcia Vergniory, Juan Luis Mañes The formalism of topological quantum chemistry (TQC) has established a powerful framework to diagnose |
Thursday, March 9, 2023 11:42AM - 11:54AM |
T19.00002: Non-Fermi Liquid Topological Semimetals Chandan Setty, Silke Buehler-Paschen, Haoyu Hu, Lei Chen, Mikel García Díez, Sarah E Grefe, Andrey Prokofiev, Stefan Kirchner, Maia Garcia Vergniory, Jennifer Cano, Qimiao Si Whether and how correlated topological states without free-electron counterparts occur |
Thursday, March 9, 2023 11:54AM - 12:06PM |
T19.00003: Electronic structure of a topological Kondo magnet Zijia Cheng, Yuqing Huang, Pengyu Zheng, Tyler A Cochran, Xian Yang, Zhiping Yin, Shuang Jia, Zahid M Hasan Magnetic topological semimetals have recently emerged as a topic of central interest in condensed matter physics, but have mostly been explored in weakly-correlated systems. Here, we report the topological electronic structure of a new strong-correlated magnet, through Angular-Resolved Photoemission Spectroscopy (ARPES) combined with DFT+DMFT calculations. Remarkably, we experimentally observe a strong Kondo coherence peak below magnetic transition temperature, which indicates the coexistence of the Kondo lattice and magnetism in the system. We further observe band crossings between the heavy band and itinerant band. DFT+DMFT calculation shows the non-trivial topology of the band crossings. Through comparing with the electronic structure of the similar compound that doesn’t have Kondo physics, we demonstrate the crucial role of Kondo-driven topological electronic structure in understanding the exotic transport responses of the compound. |
Thursday, March 9, 2023 12:06PM - 12:18PM |
T19.00004: Topological semimetal driven by strong correlations and crystalline symmetry Lei Chen, Maia Garcia Vergniory, Chandan Setty, Haoyu Hu, Sarah Grefe, Lukas Fischer, Xinlin Yan, Gaku Eguchi, Andrey Prokofiev, Silke Buehler-Paschen, Jennifer Cano, Qimiao Si Whether and how electron correlations influence electronic topology is an outstanding question. Weyl-Kondo semimetal has become a rare prototype to realize gapless topological states driven by strong correlations [1-4]. Here [5], we advance a general approach, in which strong correlations cooperate with crystalline symmetry to drive gapless topological states. We describe how to apply this materials design principle to discover new electronic topological states in square-net lattices (particularly a Weyl-Kondo nodal-line semimetal), identify three heavy fermion compounds as new candidates, provide first experimental evidence for our prediction in Ce2Au3In5, and discuss how our approach may lead to many more. Finally, using the nonperturbative extended dynamical mean field method, we realize a Weyl-Kondo quantum critical point and describe its topological characteristics [6]. |
Thursday, March 9, 2023 12:18PM - 12:30PM |
T19.00005: Nonlinear optical properties of Weyl-Kondo semimetals Sarah E Grefe, Jian-Xin Zhu Recently, the generation of higher-harmonic nonlinear responses via high-intensity pulse probes of solid-state materials was proposed to indicate many-body properties (such as charge dynamics) associated with strong correlations, as well as detect nontrivial topology through Berry curvature contributions to the second harmonic. However, finding suitable platforms to determine how and which higher order harmonic spectral features correspond to band structure properties have been challenging. In light of the discovery of strong-correlation-driven topology in both experimental1-3 and theoretical4-5 studies of a Weyl-Kondo semimetal (WKSM), we study the high-harmonic generation (HHG) of the WKSM. Using a Peierls-substituted noncentrosymmetric periodic Anderson model including spin orbit coupling, we contrast the response of the WKSM phase with a topologically trivial Kondo insulator and an uncorrelated Weyl semimetal. We further uncover the significance of features of HHG spectra to many-body dynamics and nontrivial band topology. |
Thursday, March 9, 2023 12:30PM - 12:42PM |
T19.00006: Classifications of Interacting Topological Crystalline Semimetals Sheng-Jie Huang, Jiabin Yu, Ruixing Zhang Topological crystalline semimetals are a class of semimetallic materials with a nontrivial interplay between the topology in the momentum space and crystalline symmetry. In order to describe topological semimetals with strong interactions, it's desirable to develop a general framework that does not rely on the band theory. We show that the general framework for classifying crystalline symmetry protected topological phases, dubbed the topological crystal approach, is also useful for classifying the topological crystalline semimetals with strong interactions. To illustrate the main idea, we apply the topological crystal method to 3d Dirac semimetals protected by $C_n$ rotation, $z$-translation, and the combined parity and time-reversal symmetries. We show that the anomaly nature of the 3d Dirac semimetals is the filling anomaly in the one-dimensional subspace at the rotational axis, and the non-interacting $Z$ classification generally reduces to an $Z_p$ subgroup under strong interactions, where $p$ is a function of $n$. We also discuss the topological response theory and derive the classification from it through coupling to the crystalline gauge fields. Our work provides a general theoretical framework to classify and characterize interacting topological crystalline semimetals. |
Thursday, March 9, 2023 12:42PM - 12:54PM |
T19.00007: What is the relation between activation energy and band gap in a 2D insulator? Yi Huang, Brian J Skinner, Boris I Shklovskii What can one actually tell about the band gap from the activation energy for conductivity in a 2D material? At first glance, it seems like the activation energy should be equal to half the band gap if the Fermi level is in the middle of the gap. But this simple relation is often strongly violated in experiments, where it is common to observe a much smaller activation energy. In this poster, I will review some examples of relevant experiments in topological insulators thin films, bilayer graphene, and Mott insulators in twisted moiré bilayers. We will show theoretically how disorder, even when present at a very low level, almost inevitably lowers the activation energy to a nonuniversal value that is parametrically smaller than the band gap. We will further show how a sufficiently large disorder can produce an apparent insulator-to-metal transition. |
Thursday, March 9, 2023 12:54PM - 1:06PM |
T19.00008: Spin Hall conductivity of interacting two-dimensional electron systems Maxim Dzero, Alex Levchenko We consider two-dimensional electron system subjected to a short-ranged nonmagnetic disorder potential, Coulomb interactions, and Rashba spin-orbit coupling. The path-integral approach incorporated within the Keldysh formalism is used to derive the kinetic equation for the semiclassical Green's function and applied to compute the spin current within the linear response theory. We discuss the frequency dependence of the spin Hall conductivity and further elucidate the role of electron interactions at finite temperatures both for the ballistic and diffusive regimes of transport. We argue that interaction corrections to the spin Hall effect stem from the quantum interference processes whose magnitude is estimated in terms of parameters of the considered model. |
Thursday, March 9, 2023 1:06PM - 1:18PM |
T19.00009: Generalized Thouless pumps in (1+1)-dimensional interacting fermionic systems Shuhei Ohyama, Masatoshi Sato, Ken Shiozaki Background The Thouless pump is a phenomenon in which U(1) electric charges are pumped from an edge of a system to another edge. The Thouless pump was originally proposed for a system in 1+1 dimension. However, it is known that such a pumping phenomenon exists in various dimensions. There are also many variations on the charge to be pumped, such as a model in which the fermion parity is pumped instead of the U(1) charge. These are collectively called generalized Thouless pumps. Such a pumping phenomenon is considered to be a general phenomenon for systems described by Short Range Entangled (SRE) states. These results, however, are for a system without interaction, and the stability of the system with interaction and the quantities that characterize the pump phenomenon are not known. |
Thursday, March 9, 2023 1:18PM - 1:30PM |
T19.00010: Bulk and edge invariants for parametrized quantum systems with symmetry Marvin Qi, Michael Hermele, Xueda Wen Parametrized quantum systems are a generalization of conventional topological phases of matter, where one considers families of gapped many-body systems which depend continuously on some external parameters. Familiar nontrivial examples include the spin-1/2 particle in a magnetic field and the Thouless charge pump. We construct new examples of parametrized quantum systems via the suspension isomorphism, which can be thought of as "higher" analogues of Thouless pumps. We develop bulk and boundary topological invariants which characterize such paramterized quantum systems, and establish a concrete bulk-boundary correspondence in certain cases. |
Thursday, March 9, 2023 1:30PM - 1:42PM |
T19.00011: Bosonization of the interacting Su-Schrieffer-Heeger model Tony Jin, Paola Ruggiero, Thierry Giamarchi One of the simplest model capturing the key features of topological insulators is the Su-Shrieffer-Heeger (SSH) model which consists of a 1D tight-binding model with alternating bond value. Although the SSH is now considered as a textbook model for topological insulators, the inclusion of interactions in this model remains to this day an open question. In this work, we apply the bosonization procedure to treat interactions in the SSH model with open boundaries. We use the classical Euler-Lagrange equations of motions of the bosonized theory to compute the density profile of the Majorana edge mode in the topological phase. In the non-interacting case, we observe excellent agreement with numerical results obtained from exact diagonalization, notably the exponential localization of the mode near the edges. In the bosonized language, the inclusion of nearest-neighbors interactions amounts to a rescaling of the parameters of the free bosonic Hamiltonian and we derive an explicit formula for the localization length in presence of interactions. |
Thursday, March 9, 2023 1:42PM - 1:54PM |
T19.00012: Tripartite Entanglement of Topological Orders: A Diagrammatic Approach Ramanjit Sohal, Shinsei Ryu Recent studies have demonstrated that measures of tripartite entanglement can probe data characterizing topologically ordered phases to which bipartite entanglement is insensitive. Motivated by these observations, we compute the reflected entropy and logarithmic negativity, a mixed state entanglement measure, in tripartitions of bosonic topological orders using the anyon diagrammatic formalism. We consider tripartitions in which three subregions meet at trijunctions and tetrajunctions. In the former case, we find a contribution to the negativity which distinguishes between Abelian and non-Abelian order while in the latter, we find a distinct universal contribution to the reflected entropy. Finally, we demonstrate that the negativity and reflected entropy are sensitive to the $F$-symbols for configurations in which we insert an anyon trimer, for which the Markov gap, defined as the difference between the reflected entropy and mutual information, is also found to be non-vanishing. |
Thursday, March 9, 2023 1:54PM - 2:06PM |
T19.00013: Topological and Fracton Order in Arboreal Arenas Vijay B Shenoy, Nandagopal Manoj In this work, we introduce and theoretically explore, systems constructed by qubit connectivities that do not tessellate space, i. e., non-manifold structures. We construct and study quantum models, including generalized transverse field models, gauge theories, and fractonic models, on structures – arboreal arenas – based on tree graphs. This reveals many unexpected results that could provide many new opportunities: 1) We show that even the simplest Ising gauge theory on an arboreal lattice is fractonic (excitations have restricted mobilities) with a large ground state degeneracy. 2) We show that the X-cube model (a standard example of a fracton model) is fully fractonic, i. e., neither the magnetic monopole nor any of its multipoles are mobile. 3) We study the phase/phase transitions of these models, paying careful attention to boundary conditions, and obtain their phase diagrams. 4) We uncover a new class of arboreal dualities, not only providing key insights into the physics of the phases and phase transition but also offering a comprehensive and generalized view of known dualities in lattice Ising systems. 5) We undertake the classification of topological orders on arboreal arenas and discover a completely unexpected and remarkable result. There are only three types of inequivalent arboreal toric code orders on two-dimensional arboreal arenas and four types of X-cube fracton orders on three-dimensional arboreal arenas. |
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