title: First-principles method of propagation of tightly bound excitons: verifying the exciton band structure of LiF with inelastic x-ray scattering.
abstract: We propose a simple first-principles method to describe the propagation of tightly bound excitons. By viewing the exciton as a composite object (an effective Frenkel exciton in Wannier orbitals), we define an exciton kinetic kernel to encapsulate the exciton propagation and decay for all binding energies. Applied to prototypical LiF, our approach produces three exciton bands, which we verified quantitatively via inelastic x-ray scattering. The proposed real-space picture is computationally inexpensive and thus enables study of the full exciton dynamics, even in the presence of surfaces and impurity scattering. It also provides an intuitive understanding to facilitate practical exciton engineering in semiconductors, strongly correlated oxides, and their nanostructures.
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA and Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan.
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Lee
authors.forename: Xiaoqian M
authors.initials: XM
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Gan
authors.forename: Chen-Lin
authors.initials: CL
authors.lastname: Yeh
authors.forename: H C
authors.initials: HC
authors.lastname: Hsueh
authors.forename: Peter
authors.initials: P
authors.lastname: Abbamonte
authors.forename: Wei
authors.initials: W
authors.lastname: Ku