Topological exciton condensate of imbalanced electrons and holes

Abstract

I study the effects of particle-hole imbalance on the exciton superfluid formed in a topological insulator thin-film and obtain the mean-field phase diagram. At finite imbalance a spatially modulated condensate is formed, akin to the Fulde-Ferrel-Larkin-Ovchinikov state in a superconductor, which preempts a first-order transition from the uniform condensate to the normal state at low temperatures. The imbalance can be tuned by changing the chemical potential at the two surfaces separately or, alternatively, by an asymmetric application of Zeeman fields at constant chemical potential. A vortex in the condensate carries a precisely fractional charge half of that of an electron. Possible experimental signatures for realistic parameters are discussed.

4 pages, 4 figures; (v2) Figures (especially Fig. 4) are improved; Fig. 1 now shows the transition lines correctly (results are the same as before); Text is updated and typos corrected; References are updated and added. To appear in PRB

References in corpus (9)

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• Exciton condensation and charge fractionalization in a topological insulator film
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• Electron screening and excitonic condensation in double-layer graphene systems
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Cited by in corpus (17)

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• Excitonic topological order in imbalanced electron-hole bilayers
• Electron-hole pairing in topological insulator thin film
• Weak Localization and Antilocalization in Topological Materials with Impurity Spin-Orbit Interactions
• Spin-polarized tunneling current through a thin film of topological insulator in a parallel magnetic field
• Lattice model for the surface states of a topological insulator with applications to magnetic and exciton instabilities
• Tunneling and Fluctuating Electron-Hole Cooper Pairs in Double Bilayer Graphene
• Majorana edge modes of topological exciton condensate with superconductors
• Screening, Friedel oscillations and low-temperature conductivity in topological insulator thin films
• Anomalous Coulomb Drag in Electron-Hole Bilayers due to the Formation of Excitons
• Chiral Topological Excitons in a Chern Band Insulator
• Topological Larkin-Ovchinnikov phase and Majorana zero mode chain in bilayer superconducting topological insulator films
• Non-Abelian braiding in spin superconductors utilizing the Aharonov-Casher effect
• Fluctuational internal Josephson effect in topological insulator film
• Topological fluctuating electron-hole Cooper pairs in graphene-GaAs heterostructures
• Gapless chiral excitons in thin films of topological insulators
• Anomalous drag in electron-hole condensates with granulated order