On-chip detection of anisotropic thermopolarization in quartz

TL;DR

This paper demonstrates that heating in quartz induces mechanical stress leading to electrical signals via electromechanical coupling, revealing a thermomechanical pathway for heat-to-charge conversion and enabling anisotropic response probing.

Contribution

It introduces an on-chip method to detect anisotropic thermopolarization in quartz through thermally generated stress and electrical signals, highlighting a new thermomechanical conversion pathway.

Findings

Heat induces measurable electrical signals via stress in quartz.

The device detects anisotropic piezoelectric responses in X-cut and Z-cut crystals.

Electrical signals can be measured in both current and voltage modes.

Abstract

Temperature gradients are widely used to drive and probe transport phenomena in solids, forming the basis of heat-to-charge conversion processes. In typical experiments, local heating is introduced to generate a temperature gradient, and the resulting electrical response is detected by separate electrodes. Such measurements usually regard heating purely as a source of thermal excitation. Here, we show that heating inherently generates mechanical stress through thermal expansion, which in turn produces measurable electrical signals via electromechanical coupling. Using quartz as a model piezoelectric system, we demonstrate that heat can be converted to electrical currents via thermally generated stress. The on-chip device used in our experiment enables us to probe the anisotropy of the piezoelectric tensor through the thermally generated current, exhibiting twofold and threefold responses for X-cut and Z-cut crystals, respectively. We further show that the response can be detected in both current and voltage modes. These results reveal a thermomechanical pathway for heat-to-charge conversion and establish a general platform for electrically probing thermomechanical responses in insulating materials.