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arXiv 1503.00679cond-mat.mtrl-sci
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静电控制增强层状铁电体的体光伏效应

Bulk photovoltaic effect enhancement via electrostatic control in layered ferroelectrics

Fenggong Wang, Steve M. Young, Fan Zheng, Ilya Grinberg, Andrew M. Rappe

摘要:

铁电钙钛矿氧化物的体光伏效应(BPVE)的漂移电流机制与结构和电子性质之间的关系还没有得到很好的理解。本文从第一性原理出发,研究了具有可见光吸收的铁电体Pb(Ni $_{x}$ Ti $_{1-x}$)O $_{3-x}$固溶体的位移电流光伏效应。我们发现,共价轨道字符指示的方向,幅度和起始能量的移位电流在一个可预测的方式。特别是,我们发现,移位电流响应可以通过在层状铁电体中的静电控制来增强,因为束缚电荷面临更强的动力来屏蔽较厚材料中的电场,使电子密度离域。这种具有交替光电流产生层和绝缘层的异质分层结构是BPVE应用的理想选择。

英文摘要:

The correlation between the shift current mechanism for the bulk photovoltaic effect (BPVE) and the structural and electronic properties of ferroelectric perovskite oxides is not well understood. Here, we study and engineer the shift current photovoltaic effect using a visible-light-absorbing ferroelectric Pb(Ni$_{x}$Ti$_{1-x}$)O$_{3-x}$ solid solution from first principles. We show that the covalent orbital character dicates the direction, magnitude, and onset energy of shift current in a predictable fashion. In particular, we find that the shift current response can be enhanced via electrostatic control in layered ferroelectrics, as bound charges face a stronger impetus to screen the electric field in a thicker material, delocalizing electron densities. This heterogeneous layered structure with alternative photocurrent generating and insulating layers is ideal for BPVE applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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