The excitonic spectra of single-layer GeS and GeSe are predicted by ab initio GW and Bethe-Salpeter equation calculations. G0W0 calculations for the band structures find a fundamental band gap of 2.85 eV for GeS and 1.70 eV for GeSe monolayer. However, excitons are tightly bound, specially in GeS at the Γ point, where the quasiparticle interactions are so strong that they shift the Γ exciton peak energy into the visible range and below the off-Γ exciton peak. The lowest energy excitons in both materials are excited by light along the zigzag direction and have exciton binding energies of 1.05 and 0.4 eV, respectively; but despite the strong binding, the calculated binding energies are in agreement with a Mott-Wannier model.
Strongly bound Mott-Wannier excitons in GeS and GeSe monolayers
Trevisanutto P. E.;
2016-01-01
Abstract
The excitonic spectra of single-layer GeS and GeSe are predicted by ab initio GW and Bethe-Salpeter equation calculations. G0W0 calculations for the band structures find a fundamental band gap of 2.85 eV for GeS and 1.70 eV for GeSe monolayer. However, excitons are tightly bound, specially in GeS at the Γ point, where the quasiparticle interactions are so strong that they shift the Γ exciton peak energy into the visible range and below the off-Γ exciton peak. The lowest energy excitons in both materials are excited by light along the zigzag direction and have exciton binding energies of 1.05 and 0.4 eV, respectively; but despite the strong binding, the calculated binding energies are in agreement with a Mott-Wannier model.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
