TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.17.5.137
TI  - Topological dipole insulator
PY  - 2024/11/18
UR  - https://scipost.org/SciPostPhys.17.5.137
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 17
IS  - 5
SP  - 137
A1  - Lam, Ho Tat
AU  - Han, Jung Hoon
AU  - You, Yizhi
AB  - We expand the concept of two-dimensional topological insulators to encompass a novel category known as topological dipole insulators (TDIs), characterized by conserved dipole moments along the $x$-direction in addition to charge conservation. By generalizing Laughlin's flux insertion argument, we prove a no-go theorem and predict possible edge patterns and anomalies in a TDI with both charge $U^e(1)$ and dipole $U^d(1)$ symmetries. The edge of a TDI is characterized as a quadrupolar channel that displays a dipole $U^d(1)$ anomaly. A quantized amount of dipole gets transferred between the edges under the dipolar flux insertion, manifesting as 'quantized quadrupolar Hall effect' in TDIs. A microscopic coupled-wire Hamiltonian realizing the TDI is constructed by introducing a mutually commuting pair-hopping terms between wires to gap out all the bulk modes while preserving the dipole moment. The effective action at the quadrupolar edge can be derived from the wire model, with the corresponding bulk dipolar Chern-Simons response theory delineating the topological electromagnetic response in TDIs. Finally, we enrich our exploration of topological dipole insulators to the spinful case and construct a dipolar version of the quantum spin Hall effect, whose boundary evidences a mixed anomaly between spin and dipole symmetry. Effective bulk and the edge action for the dipolar quantum spin Hall insulator are constructed as well.
ER  -

@Article{10.21468/SciPostPhys.17.5.137,
	title={{Topological dipole insulator}},
	author={Ho Tat Lam and Jung Hoon Han and Yizhi You},
	journal={SciPost Phys.},
	volume={17},
	pages={137},
	year={2024},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.17.5.137},
	url={https://scipost.org/10.21468/SciPostPhys.17.5.137},
}