Department of Physics, University of California, Berkeley, CA 94720, USA.
Proc Natl Acad Sci U S A. 2012 Jun 19;109(25):9710-5. doi: 10.1073/pnas.1117990109. Epub 2012 May 30.
The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.
原子级别的材料界面控制已经产生了新颖的界面性质和功能。特别是，对复杂氧化物界面处的极性不连续性的研究处于现代凝聚态物质研究的前沿。在这里，我们采用实验测量和理论计算相结合的方法，证明了通过精确的原子尺度界面工程控制异质外延双层体的铁电极化这一整体性质。更具体地说，通过利用界面的价态失配来影响界面处的静电势跃变来实现这种控制，这表现为铁电滞后回线中的偏置电压，并决定了铁电状态。对由不同铁电体和导电钙钛矿底层组成的各种系统的广泛研究扩展了这一现象的普遍性。
