文章基本信息

标题：Giant photovoltaic effects driven by residual polar field within unit-cell-scale LaAlO3 films on SrTiO3
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作者：Haixing Liang ; Long Cheng ; Xiaofang Zhai 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2013
卷号：3
期号：1
DOI：10.1038/srep01975
语种：English
出版社：Springer Nature
摘要：For polar/nonpolar heterostructures, Maxwell's theory dictates that the electric potential in the polar components will increase divergently with the film thickness. For LaAlO₃/SrTiO₃, a conceptually intriguing route, termed charge reconstruction, has been proposed to avert such “polar catastrophe”. The existence of a polar potential in LaAlO₃ is a prerequisite for the validity of the charge reconstruction picture, yet to date, its direct measurement remains a major challenge. Here we establish unambiguously the existence of the residual polar potential in ultrathin LaAlO₃ films on SrTiO₃, using a novel photovoltaic device design as an effective probe. The measured lower bound of the residual polar potential is 1.0 V. Such a direct observation of the giant residual polar potential within the unit-cell-scale LaAlO₃ films amounts to a definitive experimental evidence for the charge reconstruction picture, and also points to new technological significance of oxide heterostructures in photovoltaic and sensing devices with atomic-scale control.