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Excitons in van derWaals materials: From monolayer to bulk hexagonal boron nitride

TitleExcitons in van derWaals materials: From monolayer to bulk hexagonal boron nitride
Publication TypeJournal Article
Year of Publication2017
AuthorsKoskelo, J., Fugallo G., Hakala M., Gatti M., Sottile F., & Cudazzo P.
Abstract

We present a general picture of the exciton properties of layered materials in terms of the excitations of their single-layer building blocks. To this end, we derive a model excitonic Hamiltonian by drawing an analogy with molecular crystals, which are other prototypical van der Waals materials. We employ this simplified model to analyze in detail the excitation spectrum of hexagonal boron nitride (hBN) that we have obtained from the ab initio solution of the many-body Bethe-Salpeter equation as a function of momentum. In this way, we identify the character of the lowest-energy excitons in hBN, discuss the effects of the interlayer hopping and the electron-hole exchange interaction on the exciton dispersion, and illustrate the relation between exciton and plasmon excitations in layered materials.

JournalPHYSICAL REVIEW B
Volume95
DOI10.1103/PhysRevB.95.035125
Date PublishedJAN 17
Type of ArticleArticle
Citation Key ISI:000392071700003