Prediction of a topological p + ip excitonic insulator with parity anomaly

Rui Wang, Onur Erten, Baigeng Wang, D. Y. Xing

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Excitonic insulators are insulating states formed by the coherent condensation of electron and hole pairs into BCS-like states. Isotropic spatial wave functions are commonly considered for excitonic condensates since the attractive interaction among the electrons and the holes in semiconductors usually leads to s-wave excitons. Here, we propose a new type of excitonic insulator that exhibits order parameter with p + ip symmetry and is characterized by a chiral Chern number Cc = 1/2. This state displays the parity anomaly, which results in two novel topological properties: fractionalized excitations with e/2 charge at defects and a spontaneous in-plane magnetization. The topological insulator surface state is a promising platform to realize the topological excitonic insulator. With the spin-momentum locking, the interband optical pumping can renormalize the surface electrons and drive the system towards the proposed p + ip instability.

Original languageEnglish (US)
Article number210
JournalNature Communications
Volume10
Issue number1
DOIs
StatePublished - Dec 1 2019

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Parity
parity
insulators
Electrons
anomalies
predictions
Optical pumping
Semiconductors
Beam plasma interactions
Surface states
Wave functions
electrons
Condensation
Magnetization
Momentum
optical pumping
Semiconductor materials
locking
condensates
Defects

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Prediction of a topological p + ip excitonic insulator with parity anomaly. / Wang, Rui; Erten, Onur; Wang, Baigeng; Xing, D. Y.

In: Nature Communications, Vol. 10, No. 1, 210, 01.12.2019.

Research output: Contribution to journalArticle

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