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Title: Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers

Abstract

In this paper, we present a theory of optical absorption by interlayer excitons in a heterobilayer formed from transition metal dichalcogenides. The theory accounts for the presence of small relative rotations that produce a momentum shift between electron and hole bands located in different layers, and a moire pattern in real space. Because of the momentum shift, the optically active interlayer excitons are located at the moire Brillouin zone's corners, instead of at its center, and would have elliptical optical selection rules if the individual layers were translationally invariant. We show that the exciton moire potential energy restores circular optical selection rules by coupling excitons with different center of mass momenta. A variety of interlayer excitons with both senses of circular optical activity, and energies that are tunable by twist angle, are present at each valley. The lowest energy exciton states are generally localized near the exciton potential energy minima. Finally, we discuss the possibility of using the moire pattern to achieve scalable two-dimensional arrays of nearly identical quantum dots.

Authors:
 [1];  [2];  [2]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Univ. of Texas, Austin, TX (United States). Department of Physics
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; U.S. Army Research Laboratory - U.S. Army Research Office (ARO); Welch Foundation; USDOE
OSTI Identifier:
1419946
Alternate Identifier(s):
OSTI ID: 1417696
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 3; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE

Citation Formats

Wu, Fengcheng, Lovorn, Timothy, and MacDonald, A. H.. Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.97.035306.
Wu, Fengcheng, Lovorn, Timothy, & MacDonald, A. H.. Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers. United States. doi:10.1103/PhysRevB.97.035306.
Wu, Fengcheng, Lovorn, Timothy, and MacDonald, A. H.. Mon . "Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers". United States. doi:10.1103/PhysRevB.97.035306.
@article{osti_1419946,
title = {Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers},
author = {Wu, Fengcheng and Lovorn, Timothy and MacDonald, A. H.},
abstractNote = {In this paper, we present a theory of optical absorption by interlayer excitons in a heterobilayer formed from transition metal dichalcogenides. The theory accounts for the presence of small relative rotations that produce a momentum shift between electron and hole bands located in different layers, and a moire pattern in real space. Because of the momentum shift, the optically active interlayer excitons are located at the moire Brillouin zone's corners, instead of at its center, and would have elliptical optical selection rules if the individual layers were translationally invariant. We show that the exciton moire potential energy restores circular optical selection rules by coupling excitons with different center of mass momenta. A variety of interlayer excitons with both senses of circular optical activity, and energies that are tunable by twist angle, are present at each valley. The lowest energy exciton states are generally localized near the exciton potential energy minima. Finally, we discuss the possibility of using the moire pattern to achieve scalable two-dimensional arrays of nearly identical quantum dots.},
doi = {10.1103/PhysRevB.97.035306},
journal = {Physical Review B},
number = 3,
volume = 97,
place = {United States},
year = {Mon Jan 22 00:00:00 EST 2018},
month = {Mon Jan 22 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 22, 2019
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Cited by: 7 works
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Works referenced in this record:

Vertical and in-plane heterostructures from WS2/MoS2 monolayers
journal, September 2014

  • Gong, Yongji; Lin, Junhao; Wang, Xingli
  • Nature Materials, Vol. 13, Issue 12, p. 1135-1142
  • DOI: 10.1038/nmat4091