Interlayer excitons in MoSe2/WSe2 heterostructures from first principles

Gillen R, Maultzsch J (2018)


Publication Language: English

Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Publisher: AMER PHYSICAL SOC

Book Volume: 97

Journal Issue: 16

DOI: 10.1103/PhysRevB.97.165306

Open Access Link: https://arxiv.org/abs/1801.06310

Abstract

Based on ab initio theoretical calculations of the optical spectra of vertical heterostructures of MoSe2 (or MoS2) and WSe2 sheets, we reveal two spin-orbit-split Rydberg series of excitonic states below the A excitons of MoSe2 and WSe2 with a significant binding energy on the order of 250 meV for the first excitons in the series. At the same time, we predict from accurate many-body G(0)W(0) calculations that crystallographically aligned MoSe2/WSe2 heterostructures exhibit an indirect fundamental band gap. Due to the type-II nature of the MoSe2/WSe2 heterostructure, the indirect transition and the exciton Rydberg series corresponding to a direct transition exhibit a distinct interlayer nature with spatial charge separation of the coupled electrons and holes. Our calculations confirm the recent experimental observation of a doublet nature of the long-lived states in photoluminescence spectra of MoX2/WY2 heterostructures, and we attribute these two contributions to momentum-direct interlayer excitons at the K point of the hexagonal Brillouin zone and to momentum-indirect excitons at the indirect fundamental band gap. Our calculations further suggest a noticeable effect of stacking order on the electronic band gaps and on the peak energies of the interlayer excitons and their oscillation strengths.

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How to cite

APA:

Gillen, R., & Maultzsch, J. (2018). Interlayer excitons in MoSe2/WSe2 heterostructures from first principles. Physical Review B, 97(16). https://doi.org/10.1103/PhysRevB.97.165306

MLA:

Gillen, Roland, and Janina Maultzsch. "Interlayer excitons in MoSe2/WSe2 heterostructures from first principles." Physical Review B 97.16 (2018).

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