Topological excitonic insulators in electron bilayers modulated by twisted hBN

Fuente: arXiv
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Autores principales: Zeng, Yongxin, MacDonald, Allan H., Wei, Nemin
Formato: Preprint
Publicado: 2025
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author Zeng, Yongxin
MacDonald, Allan H.
Wei, Nemin
author_facet Zeng, Yongxin
MacDonald, Allan H.
Wei, Nemin
contents Equilibrium interlayer exciton condensation is common in bilayer quantum Hall systems and is characterized by spontaneous phase coherence between isolated layers. It has been predicted that similar physics can occur in the absence of a magnetic field in some two-dimensional semiconductor bilayers. In this work we consider the case of two transition metal dichalcogenide (TMD) monolayers separated by a twisted hexagonal boron nitride (hBN) bilayer or multilayer. The hBN layers suppress tunneling between the TMD layers so that phase coherence is spontaneous when it is present. When twisted, the hBN layers also form a ferroelectric moiré pattern that applies opposite triangular-lattice modulation potentials to the two TMD layers. We show via mean-field theory that at total hole filling per moiré unit cell $ν=1$, this geometry can favor a chiral p-wave exciton condensate state in which the quantum anomalous Hall effect coexists with counter-flow superfluidity. We present a mean-field phase diagram for TMD hole bilayers modulated by twisted hBN, discuss the conditions needed for the realization of the p-wave condensate state, and propose experiments that could confirm its presence.
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id arxiv_https___arxiv_org_abs_2509_11041
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Topological excitonic insulators in electron bilayers modulated by twisted hBN
Zeng, Yongxin
MacDonald, Allan H.
Wei, Nemin
Mesoscale and Nanoscale Physics
Equilibrium interlayer exciton condensation is common in bilayer quantum Hall systems and is characterized by spontaneous phase coherence between isolated layers. It has been predicted that similar physics can occur in the absence of a magnetic field in some two-dimensional semiconductor bilayers. In this work we consider the case of two transition metal dichalcogenide (TMD) monolayers separated by a twisted hexagonal boron nitride (hBN) bilayer or multilayer. The hBN layers suppress tunneling between the TMD layers so that phase coherence is spontaneous when it is present. When twisted, the hBN layers also form a ferroelectric moiré pattern that applies opposite triangular-lattice modulation potentials to the two TMD layers. We show via mean-field theory that at total hole filling per moiré unit cell $ν=1$, this geometry can favor a chiral p-wave exciton condensate state in which the quantum anomalous Hall effect coexists with counter-flow superfluidity. We present a mean-field phase diagram for TMD hole bilayers modulated by twisted hBN, discuss the conditions needed for the realization of the p-wave condensate state, and propose experiments that could confirm its presence.
title Topological excitonic insulators in electron bilayers modulated by twisted hBN
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2509.11041