激子
单层
结合能
比克西顿
激发态
凝聚态物理
蓝移
物理
原子物理学
分子物理学
材料科学
光致发光
纳米技术
光电子学
作者
Pushpendra Yadav,Bramhachari Khamari,Bahadur Singh,K. V. Adarsh,Amit Agarwal
标识
DOI:10.1088/1361-648x/acc43f
摘要
Reduced dielectric screening in two-dimensional materials enables bound excitons, which modifies their optical absorption and optoelectronic response. Here, we demonstrate the existence of excitons in the bandgap of the monolayer family of the newly discovered syntheticMoSi2Z4(Z=N, P, and As) series of materials. All three monolayers support several bright and strongly bound excitons with binding energies varying from 1 eV to 1.35 eV for the lowest energy exciton resonances. We show that on increasing the pump fluence or photo-excited carrier density, the lowest energy exciton first undergoes a redshift followed by a blueshift, due to the renormalized exciton binding energies. The exciton binding energy varies as a Lennard-Jones-like potential as a function of the inter-exciton spacing. This establishes an atom-like attractive and repulsive interaction between excitons depending on the inter-exciton separation. Our study shows that theMoSi2Z4series of monolayers offer an exciting test-bed for exploring the physics of strongly bound excitons and their non-equilibrium dynamics.
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