Polaron spectroscopy of a bilayer excitonic insulator

Amelio, Ivan and Drummond, Neil and Demler, Eugene and Schmidt, Richard and Imamoglu, Atac (2023) Polaron spectroscopy of a bilayer excitonic insulator. Physical Review B: Condensed Matter and Materials Physics, 107: 155303. ISSN 1098-0121

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Abstract

Recent advances in fabrication of two-dimensional materials and their moiré heterostructures have opened up new avenues for realization of ground-state excitonic insulators, where the structure spontaneously develops a finite interlayer electronic polarization. We propose and analyze a scheme where an optically generated intralayer exciton is screened by excitations out of the excitonic insulator to form interlayer polarons. Using quantum Monte Carlo calculations we first determine the binding energy of the biexciton state composed of inter- and intralayer excitons, which plays a central role in understanding polaron formation. We describe the excitations out of the ground-state condensate using BCS theory and use a single interacting-quasiparticle-pair excitation Ansatz to describe dynamical screening of optical excitations. Our predictions carry the hallmarks of the excitonic insulator excitation spectrum and show how changing the interlayer exciton binding energy by increasing the layer separation modifies the optical spectra.

Item Type:
Journal Article
Journal or Publication Title:
Physical Review B: Condensed Matter and Materials Physics
Uncontrolled Keywords:
Research Output Funding/no_not_funded
Subjects:
?? no - not funded ??
ID Code:
192952
Deposited By:
Deposited On:
10 May 2023 13:30
Refereed?:
Yes
Published?:
Published
Last Modified:
12 Jun 2024 00:49