Electro-optic Response in Germanium Halide Perovskites

Grant W. Walters, Edward H. Sargent

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


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
Issue number5
StatePublished - Feb 13 2018
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2021-04-06
Acknowledged KAUST grant number(s): KUS-11-009-21
Acknowledgements: The work presented in this publication was supported by funding from an award (KUS-11-009-21) from the King Abdullah University of Science and Technology, the Ontario Research Fund, the Ontario Research Fund Research Excellence Program, and the Natural Sciences and Engineering Research Council (NSERC) of Canada. Computations were performed on the General Purpose Cluster supercomputer at
the SciNet HPC Consortium. SciNet is funded by the Canada Foundation for Innovation under the auspices of Compute Canada; the Government of Ontario; Ontario Research Fund -Research Excellence; and the University of Toronto. The authors thank O. Voznyy and A. Jain for useful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • General Materials Science


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