2017/11/22 by Shiyuan Gao, Li Yang, Catalin D. Spataru · 2 citations
Chemistry · Materials Science · Physics and Astronomy · #2D Materials and Applications #Atomic physics #Bilayer #Chemistry #Condensed matter physics #Coupling (piping) #Dipole #Excited state #Exciton #Graphene research and applications #Heterojunction #MXene and MAX Phase Materials #Materials science #Molecule #Optoelectronics #Oscillator strength #Physics #Quantum mechanics #Spectral line #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.comp-ph #van der Waals force
paper · pdf · doi:10.1021/acs.nanolett.7b04021
published as Nano Letters, 17, 7809 (2017) · 16 pages with 4 figures and 1 table
openalex publication_date 2017/11/22 · arxiv created 2017/12/13 · arxiv updated 2017/12/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
have attracted much attention recently, particularly because of their type II band alignments and the formation of interlayer exciton as the lowest-energy excitonic state. In this work, we calculate the electronic and optical properties of such heterostructures with the first-principles GW+Bethe-Salpeter Equation (BSE) method and reveal the important role of interlayer coupling in deciding the excited-state properties, including the band alignment and excitonic properties. Our calculation shows that due to the interlayer coupling, the low energy excitons can be widely tuned by a vertical gate field. In particular, the dipole oscillator strength and radiative lifetime of the lowest energy exciton in these bilayer heterostructures is varied by over an order of magnitude within a practical external gate field. We also build a simple model that captures the essential physics behind this tunability and allows the extension of the ab initio results to a large range of electric fields. Our work clarifies the physical picture of interlayer excitons in bilayer vdW heterostructures and predicts a wide range of gate-tunable excited-state properties of 2D optoelectronic devices.