Band Bending and Ratcheting Explain Triboelectricity in a Flexoelectric Contact Diode

Triboelectricity was recognized millennia ago, but the fundamental mechanism of charge transfer is still not understood. We have recently proposed a model where flexoelectric band bending due to local asperity contacts drives triboelectric charge transfer in non-metals. While this ab initio model is consistent with a wide range of observed phenomena, to date there have been no quantitative analyses of the proposed band bending. In this work we use a Pt0.8Ir0.2 conductive atomic force microscope probe to simultaneously deform a Nb-doped SrTiO3 sample and collect current-bias data. The current that one expects based upon an analysis including the relevant flexoelectric band bending for a deformed semiconductor quantitively agrees with the experiments. The analysis indicates a general ratcheting mechanism for triboelectric transfer and strong experimental evidence that flexoelectric band bending is of fundamental importance for triboelectric contacts.

Automated summary

Triboelectric charge transfer is a complex and important phenomenon whose fundamental mechanism is still not fully understood. Recent research has proposed a model suggesting that flexoelectric band bending due to local asperity contacts is the main driving force for triboelectric charge transfer in non-metals. Experimental analysis of a doped semiconductor sample using a conductive atomic force microscope probe confirms the theoretical model, providing strong evidence for the significant role of flexoelectric band bending in triboelectric contacts.