Electro-optic Response in Germanium Halide Perovskites

Grant W. Walters, Edward H. Sargent

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Electro-optic materials that can be solution-processed and provide high-crystalline quality are sought for the development of compact, efficient optical modulators. Here we present density functional theory investigations of the linear electro-optic coefficients of candidate materials cesium and methylammonium germanium halide perovskites. As with their lead halide counterparts, these compounds can be solution-processed, but in contrast, they possess the noncentrosymmetric crystal structures needed to provide a linear electro-optic effect. We find substantial electro-optic responses from these compounds; in particular, for the r51 tensor element of CsGeI3, we predict an electro-optic coefficient of 47 pm·V-1 at the communications wavelength of 1550 nm, surpassing the strongest coefficient of LiNbO3 at 31 pm·V-1. The strong electro-optic responses of the germanium compounds are driven by high nonlinear susceptibilities and dynamics of the germanium atoms that ultimately arise from the distorted crystal structures. Alongside the electro-optic coefficient calculations, we provide the frequency responses for the linear and nonlinear electronic susceptibilities.
Original languageEnglish (US)
Pages (from-to)1018-1027
Number of pages10
JournalThe Journal of Physical Chemistry Letters
Volume9
Issue number5
DOIs
StatePublished - Feb 13 2018
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)

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