Crystallography under external electric field

TL;DR

This paper explores how advanced X-ray diffraction techniques can detect minute structural changes in crystals under electric fields, providing insights into bond behavior and dynamic responses relevant to piezoelectric effects.

Contribution

It introduces precise measurement methods for crystal distortions under electric fields and discusses their implications for understanding chemical bonds and dynamic structural responses.

Findings

Detection of 10^{-4} Å bond length distortions

Evaluation of bond sensitivity to electric fields

Time-resolved observation of piezoelectric response

Abstract

Structural response of crystals to an applied external perturbation is important as a key for understanding microscopic origin of physical properties. Experimental investigation of structural response is a great challenge for modern structure analysis. We demonstrate how advanced X-ray diffraction techniques facilitate probing tiny (10-4 {\AA}) distortions of bond lengths under a permanent electric field. We also discuss details of the experimental procedure essential for reaching such precision. We ask whether the experiment can be used to evaluate chemical bonds in crystals by their sensitivity to an external electric field and discuss if the bond deformations can be predicted using the bond-valence model or the Bader's theory of atoms in molecules and crystals. Finally, we describe the new time-resolved studies of a structural response to a dynamical switch of applied electric field. These results give access to the time-lining of piezoelectric effect on a microsecond time scale.