@article { WOS:000742858100004,
title = {Effective field theories of topological crystalline insulators and topological crystals},
journal = {Phys. Rev. B},
volume = {105},
number = {4},
year = {2022},
month = {JAN 7},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We present a general approach to obtain effective field theories for topological crystalline insulators whose low-energy theories are described by massive Dirac fermions. We show that these phases are characterized by the responses to spatially dependent mass parameters with interfaces. These mass interfaces implement the dimensional reduction procedure such that the state of interest is smoothly deformed into a topological crystal, which serves as a representative state of a phase in the general classification. Effective field theories are obtained by integrating out the massive Dirac fermions, and various quantized topological terms are uncovered. Our approach can be generalized to other crystalline symmetry-protected topological phases and provides a general strategy to derive effective field theories for such crystalline topological phases.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.105.045112},
author = {Huang, Sheng-Jie and Hsieh, Chang-Tse and Yu, Jiabin}
}
@article { WOS:000718354400005,
title = {Dynamical fragile topology in Floquet crystals},
journal = {Phys. Rev. B},
volume = {104},
number = {18},
year = {2021},
month = {NOV 9},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Although fragile topology has been intensely studied in static crystals in terms of Wannier obstruction, it is not clear how to generalize the concept to dynamical systems. In this work we generalize the concept of fragile topology, and provide a definition of fragile topology for noninteracting Floquet crystals, which we refer to as dynamical fragile topology. In contrast to the static fragile topology defined by Wannier obstruction, dynamical fragile topology is defined for the nontrivial quantum dynamics characterized by the obstruction to static limits (OTSL). Specifically, the OTSL of a Floquet crystal is fragile if and only if it disappears after adding a symmetry-preserving static Hamiltonian in a direct-sum way preserving the relevant gaps (RGs). We further present a concrete 2 + 1D example for dynamical fragile topology, based on a model that is qualitatively the same as the dynamical model with anomalous chiral edge modes in Rudner et al. {[}Phys. Rev. X 3, 031005 (2013)]. The fragile OTSL in the 2 + 1D example exhibits anomalous chiral edge modes for a natural open boundary condition, and does not require any crystalline symmetries besides lattice translations. Our work paves the way to study fragile topology for general quantum dynamics.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.104.L180303},
author = {Yu, Jiabin and Ge, Yang and Das Sarma, Sankar}
}
@article { WOS:000707028100001,
title = {Dynamical symmetry indicators for Floquet crystals},
journal = {Nat. Commun.},
volume = {12},
number = {1},
year = {2021},
month = {OCT 13},
publisher = {NATURE PORTFOLIO},
type = {Article},
abstract = {Various exotic topological phases of Floquet systems have been shown to arise from crystalline symmetries. Yet, a general theory for Floquet topology that is applicable to all crystalline symmetry groups is still in need. In this work, we propose such a theory for (effectively) non-interacting Floquet crystals. We first introduce quotient winding data to classify the dynamics of the Floquet crystals with equivalent symmetry data, and then construct dynamical symmetry indicators (DSIs) to sufficiently indicate the inherently dynamical Floquet crystals. The DSI and quotient winding data, as well as the symmetry data, are all computationally efficient since they only involve a small number of Bloch momenta. We demonstrate the high efficiency by computing all elementary DSI sets for all spinless and spinful plane groups using the mathematical theory of monoid, and find a large number of different nontrivial classifications, which contain both first-order and higher-order 2+1D anomalous Floquet topological phases. Using the framework, we further find a new 3+1D anomalous Floquet second-order topological insulator (AFSOTI) phase with anomalous chiral hinge modes. A general theory for Floquet topology applicable to all crystalline symmetry groups is lacking. Here, the authors propose such a theory for noninteracting Floquet crystals and predict an inversion-protected Floquet higher-order topological phase with anomalous chiral hinge modes.},
doi = {10.1038/s41467-021-26092-3},
author = {Yu, Jiabin and Zhang, Rui-Xing and Song, Zhi-Da}
}
@article { WOS:000655905200001,
title = {Presence versus absence of two-dimensional Fermi surface anomalies},
journal = {Phys. Rev. B},
volume = {103},
number = {20},
year = {2021},
month = {MAY 28},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We theoretically consider Fermi surface anomalies manifesting in the temperature-dependent quasiparticle properties of two-dimensional (2D) interacting electron systems, comparing and contrasting with the corresponding three-dimensional (3D) Fermi liquid situation. In particular, employing microscopic many-body perturbative techniques, we obtain analytically the leading-order and the next-to-leading-order interaction corrections to the renormalized effective mass for three distinct physical interaction models: electron-phonon, electron-paramagnon, and electron-electron Coulomb coupling. We find that the 2D renormalized effective mass does not develop any Fermi surface anomaly due to electron-phonon interaction, manifesting O(T-2) temperature correction and thus remaining consistent with the Sommerfeld expansion of the noninteracting Fermi function, in contrast to the corresponding 3D situation where the temperature correction to the renormalized effective mass has the anomalous T-2 log T behavior. In contrast, both electron-paramagnon and electron-electron interactions lead to the anomalous O(T) corrections to the 2D effective mass renormalization in contrast to T-2 log T behavior in the corresponding 3D interacting systems. We provide detailed analytical results, and comment on the conditions under which a T-2 log T term could possibly arise in the 2D quasiparticle effective mass from electron-phonon interactions. We also compare results for the temperature-dependent specific heat in the interacting 2D and 3D Fermi systems, using the close connection between the effective mass and specific heat.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.103.205154},
author = {Buterakos, Donovan and DinhDuy Vu and Yu, Jiabin and Das Sarma, Sankar}
}