Estimating Excitonic Effects in the Absorption Spectra of Solids: Problems and Insight from a Guided Iteration Scheme

Abstract

A major obstacle for computing optical spectra of solids is the lack of reliable approximations for capturing excitonic effects within time-dependent density-functional theory. We show that the trustful prediction of strongly bound electron-hole pairs within this framework using simple approximations is still a challenge and that available promising results have to be revisited. Deriving a set of analytical formula we analyze and explain the difficulties. We deduce an alternative approximation from an iterative scheme guided by previously available knowledge, significantly improving the description of exciton binding energies. Finally, we show how one can "read" exciton binding energies from spectra determined in the random phase approximation, without any further calculation.

5 pages, 2 figures plus supplemental material

References in corpus (5)

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• Efficient ab initio calculations of bound and continuum excitons
• Excitonic effects in time-dependent density-functional theory: An analytically solvable model
• Time-dependent density-functional theory for ultrafast interband excitations
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• Including many-body effects into the Wannier-interpolated quadratic photoresponse tensor
• First-principles study of excitons in the optical spectra of silver chloride
• Excitonic effects in time-dependent density functional theory from zeros of the density response
• Wigner-Seitz truncated TDDFT approach for the calculation of exciton binding energies in solids
• Progress towards understanding ultranonlocality through the wavevector and frequency dependence of approximate exchange-correlation kernels
• Comparison of long-range corrected kernels and range-separated hybrids for excitons in solids