Kavli Affiliate: Scott K. Cushing
| First 5 Authors: Cian C. Reeves, Scott K. Cushing, Vojtech Vlcek, ,
| Summary:
Understanding how to control changes in electronic structure and related
dynamical renormalizations by external driving fields is the key for
understanding ultrafast spectroscopy and applications in electronics. Here we
focus on the band-gap’s modulation by external electric fields and uncover the
effect of band dispersion on the gap renormalization. We employ the Green’s
function formalism using the real-time Dyson expansion to account for dynamical
correlations induced by photodoping. The many-body formalism captures the
dynamics of systems with long-range interactions, carrier mobility, and
variable electron and hole effective mass. We also demonstrate that mean-field
simulations based on the Hartree-Fock Hamiltonian, which lacks dynamical
correlations, yields a qualitatively incorrect picture of band-gap
renormalization. We find the trend that increasing effective mass, thus
decreasing mobility, leads to as much as a 6% enhancement in band-gap
renormalization. Further, the renormalization is strongly dependent on the
degree of photodoping. As the screening induced by free electrons and holes
effectively reduces any long-range and interband interactions for highly
excited systems, we show that there is a specific turnover point with minimal
band-gap. We further demonstrate that the optical gap renormalization follows
the same trend though its magnitude is altered by the Moss-Burstein effect.
| Search Query: ArXiv Query: search_query=au:”Scott K. Cushing”&id_list=&start=0&max_results=3