Next Article in Journal
Virtual Prototyping and Validation of Cpps within a New Software Framework
Next Article in Special Issue
Schrödinger Theory of Electrons in Electromagnetic Fields: New Perspectives
Previous Article in Journal
Numerical and Computational Analysis of a New Vertical Axis Wind Turbine, Named KIONAS
Article Menu

Export Article

Open AccessArticle
Computation 2017, 5(1), 9; doi:10.3390/computation5010009

Excitons in Solids from Time-Dependent Density-Functional Theory: Assessing the Tamm-Dancoff Approximation

Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Jianmin Tao
Received: 21 December 2016 / Revised: 21 January 2017 / Accepted: 23 January 2017 / Published: 29 January 2017
View Full-Text   |   Download PDF [739 KB, uploaded 8 February 2017]   |  

Abstract

Excitonic effects in solids can be calculated using the Bethe-Salpeter equation (BSE) or the Casida equation of time-dependent density-functional theory (TDDFT). In both methods, the Tamm-Dancoff approximation (TDA), which decouples excitations and de-excitations, is widely used to reduce computational cost. Here, we study the effect of the TDA on exciton binding energies of solids obtained from the Casida equation using long-range-corrected (LRC) exchange-correlation kernels. We find that the TDA underestimates TDDFT-LRC exciton binding energies of semiconductors slightly, but those of insulators significantly (i.e., by more than 100%), and thus it is essential to solve the full Casida equation to describe strongly bound excitons. These findings are relevant in the ongoing search for accurate and efficient TDDFT approaches for excitons. View Full-Text
Keywords: excitons; time-dependent density-functional theory; Tamm-Dancoff approximation excitons; time-dependent density-functional theory; Tamm-Dancoff approximation
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Byun, Y.-M.; Ullrich, C.A. Excitons in Solids from Time-Dependent Density-Functional Theory: Assessing the Tamm-Dancoff Approximation. Computation 2017, 5, 9.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Computation EISSN 2079-3197 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top