Mechanism of switchable and nonswitchable short-circuit photocurrent accompanying polarization switching in Bi_0.9La_0.1FeO₃thin films

¹ School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology Chongqing, 401331, China
² Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
³ Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University Beijing 100084, China

Received: 17 September 2013
Accepted: 27 January 2014

Abstract

The short-circuit photocurrent of Bi_0.9La_0.1FeO₃ epitaxial thin films has been investigated. Switchable and nonswitchable accompanying polarization switching was observed and it can be explained well using the concepts of drift current and diffusion current controlled by the combination of oxygen vacancies, polarization and conductive domain wall. The sign of photocurrent is independent of the polarization direction when the modulation of photocurrent induced by oxygen vacancies or conductive domain walls is large enough to offset that induced by polarization. Our work provides a deep insight into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities.