We report nanoscale bandgap engineering via a local strain across the inhomogeneous ferroelectric interface, which is controlled by the visible-light-excited probe voltage. Switchable photovolatic effects and the spectral response of the photocurrent were explore to illustrate the reversible bandgap variation (~0.3eV). This local-strain-engineered bandgap has been further revealed by in situ probe-voltage-assisted valence electron energy-loss spectroscopy (EELS). Phase-field simulations and first-principle calculations were also employed for illustration of the large local strain and the bandgap variation in ferroelectric perovskite oxides. This reversible bandgap tuning in complex oxides demonstrates a framework for the understanding of the opticallyrelated behaviors (photovoltaic, photoemission, and photocatalyst effects) affected by order parameters such as charge, orbital, and lattice parameters.
@article{arxiv.1709.08788,
title = {Nanoscale Bandgap Tuning across an Inhomogeneous Ferroelectric Interface},
author = {Jing Wang and Houbing Huang and Wangqiang He and Qinghua Zhang and Danni Yang and Yuelin Zhang and Renrong Liang and Chuanshou Wang and Xingqiao Ma and Lin Gu and Longqing Chen and Ce-Wen Nan and Jinxing Zhang},
journal= {arXiv preprint arXiv:1709.08788},
year = {2017}
}