arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1202.3168cond-mat.mtrl-sci
收藏

铁电体中位移电流体光伏效应的第一性原理计算

First principles calculations of the Shift Current Bulk Photovoltaic Effect in Ferroelectrics

Steve M. Young, Andrew M. Rappe

摘要:

通过对密度泛函理论的电子结构应用“位移电流”理论,从第一性原理出发计算了铁电体BaTiO $_3$和PbTiO $_3$的体光伏响应. BaTiO $_3$的第一性原理结果再现了实验光电流的方向和大小作为光频率的函数,以及电流对光偏振的依赖性,表明移位电流是BaTiO $_3$中体光伏效应的主导机制。此外,我们详细分析了响应与材料性能之间的关系。光电流并不简单地或强烈地依赖于材料极化的大小,如先前所假设的;相反,具有离域的、沿着电流方向高度不对称的共价键合的电子状态是强移位电流增强所需的。响应依赖于外部和材料参数的复杂性表明不仅在太阳能转换中应用,而且还可以应用于传感器和开关类型的设备。

英文摘要:

We calculate the bulk photovoltaic response of the ferroelectrics BaTiO$_3$ and PbTiO$_3$ from first principles by applying "shift current" theory to the electronic structure from density functional theory. The first principles results for BaTiO$_3$ reproduce eperimental photocurrent direction and magnitude as a function of light frequency, as well as the dependence of current on light polarization, demonstrating that shift current is the dominant mechanism of the bulk photovoltaic effect in BaTiO$_3$. Additionally, we analyze the relationship between response and material properties in detail. The photocurrent does not depend simply or strongly on the magnitude of material polarization, as has been previously assumed; instead, electronic states with delocalized, covalent bonding that is highly asymmetric along the current direction are required for strong shift current enhancements. The complexity of the response dependence on both external and material parameters suggests applications not only in solar energy conversion, but to photocatalysis and sensor and switch type devices as well.

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。

↑