Signatures of subband excitons in few-layer black phosphorus

A. Chaves, G. O. Sousa, K. Khaliji, D. R. Da Costa, G. A. Farias, Tony Low

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Abstract

Recent experimental measurements of light absorption in few-layer black phosphorus (BP) revealed a series of high and sharp peaks, interspersed by pairs of lower and broader features. Here, we propose a theoretical model for these excitonic states in few-layer BP within a continuum approach for the in-plane degrees of freedom and a tight-binding approximation that accounts for interlayer couplings. This yields excitonic transitions between different combinations of the subbands created by the coupled BP layers, which leads to a series of high and low oscillator strength excitonic states, consistent with the experimentally observed bright and dark exciton peaks, respectively. The main characteristics of such subband exciton states, as well as the possibility to control their energies and oscillator strengths via applied electric and magnetic fields, are discussed, towards a full understanding of the excitonic spectrum of few-layer BP and its tunability.

Original languageEnglish (US)
Article number165428
JournalPhysical Review B
Volume103
Issue number16
DOIs
StatePublished - Apr 28 2021

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© 2021 American Physical Society.

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