Exciton-Plasmon States in Nanoscale Materials: Breakdown of the Tamm-Dancoff Approximation

Myrta Gruning, Andrea Marini, Xavier Gonze

Research output: Contribution to journalArticlepeer-review

100 Citations (Scopus)


Within the Tamm-Dancoff approximation, ab initio approaches describe excitons as packets of electron-hole pairs propagating only forward in time. However, we show that in nanoscale materials excitons and plasmons hybridize, creating exciton-plasmon states where the electron-hole pairs oscillate back and forth in time. Then, as exemplified by the trans-azobenzene molecule and the carbon nanotubes, the Tamm-Dancoff approximation yields errors larger than the accuracy claimed in ab initio calculations. Instead, we propose a general and efficient approach that avoids the Tamm-Dancoff approximation, correctly describes excitons, plasmons, and exciton-plasmon states, and provides a good agreement with experimental results.

Original languageEnglish
Pages (from-to)2820-2824
Number of pages5
JournalNano Letters
Issue number8
Publication statusPublished - 12 Aug 2009

Cite this