• Editors' Suggestion

Theory of competing excitonic orders in insulating WTe2 monolayers

Yves H. Kwan, T. Devakul, S. L. Sondhi, and S. A. Parameswaran
Phys. Rev. B 104, 125133 – Published 22 September 2021

Abstract

We develop a theory of the excitonic phase recently proposed as the zero-field insulating state observed near charge neutrality in monolayer WTe2. Using a Hartree-Fock approximation, we numerically identify two distinct gapped excitonic phases: a spin density wave state for weak nonzero interaction strength and spin spiral order at stronger interactions, separated by a narrow window of a nonexcitonic quantum spin Hall insulator. We introduce a simplified model capturing key features of the WTe2 band structure, in which these phases appear as distinct valley ferromagnetic orders. We link the competition between the excitonic phases to the orbital structure of electronic wave functions at the Fermi surface and hence its proximity to the underlying gapped Dirac point in WTe2. We briefly discuss collective modes of the two excitonic states, and comment on implications for experiments.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 18 March 2021
  • Revised 1 September 2021
  • Accepted 8 September 2021

DOI:https://doi.org/10.1103/PhysRevB.104.125133

©2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Yves H. Kwan1, T. Devakul2, S. L. Sondhi2, and S. A. Parameswaran1

  • 1Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
  • 2Department of Physics, Princeton University, Princeton, New Jersey 08540, USA

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 104, Iss. 12 — 15 September 2021

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×