2018/01/31 by Roland Gillen, Janina Maultzsch · 2 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Atomic physics #Brillouin zone #Chalcogenide Semiconductor Thin Films #Chemistry #Condensed matter physics #Crystallography #Exciton #Heterojunction #Ionization #Materials science #Optics #Perovskite Materials and Applications #Photoluminescence #Physics #Quantum mechanics #Rydberg formula #Spectral line #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.97.165306
published as Phys. Rev. B 97, 165306 (2018) · 8 pages main manuscript, 12 pages supplementary information
openalex created_date 2018/02/02 · arxiv created 2018/04/06 · openalex publication_date 2018/04/16 · arxiv updated 2018/04/18 · openalex updated_date 2026/08/05
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 G0W0 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.