标题： 近年来在体光伏效应理论方面的进展 显示英文标题

标题： Recent Progress in the Theory of Bulk Photovoltaic Effect

摘要： 体光伏效应（BPVE）发生在具有破坏反演对称性的固体中，指的是由于均匀照射产生的直流电流，而无需异质结构或界面，这是与传统光伏效应不同的特征。 它的存在几乎在50年前就已经被证明，但预测理论直到最近十年才出现，使得可以识别不同的机制并确定它们在实际材料中的相对重要性。 现在普遍认为存在一种内在机制，即位移电流，它对散射不敏感，现在第一性原理计算可以给出高度准确的预测。 另一种重要但更外在的机制，称为弹道电流，也引起了广泛关注，但由于复杂的散射过程，其在实际材料中的数值计算直到最近才成为可能。 此外，在圆偏振光下会出现一种内在的弹道电流，通常称为注入电流，并在实验中有广泛的应用。 本文回顾了与理论发展相关的实验，并重点讨论了BPVE理论及其数值实现的最新进展。 作为新发展理论能力的展示，简要介绍了由理论发展所实现的材料设计策略。 最后，讨论了BPVE领域中存在的问题和可能的未来方向，以激发进一步的研究。 显示英文摘要

摘要： The bulk photovoltaic effect (BPVE) occurs in solids with broken inversion symmetry and refers to DC current generation due to uniform illumination, without the need of heterostructures or interfaces, a feature that is distinct from the traditional photovoltaic effect. Its existence has been demonstrated almost 50 years ago, but predictive theories only appeared in the last ten years, allowing for the identification of different mechanisms and the determination of their relative importance in real materials. It is now generally accepted that there is an intrinsic mechanism that is insensitive to scattering, called shift current, where first-principles calculations can now give highly accurate predictions. Another important but more extrinsic mechanism, called ballistic current, is also attracting a lot of attention, but due to the complicated scattering processes, its numerical calculation for real materials is only made possible quite recently. In addition, an intrinsic ballistic current, usually referred to as injection current, will appear under circularly-polarized light and has wide application in experiments. In this article, experiments that are pertinent to the theory development are reviewed, and a significant portion is devoted to discussing the recent progress in the theories of BPVE and their numerical implementations. As a demonstration of the capability of the newly developed theories, a brief review of the materials design strategies enabled by the theory development is given. Finally, remaining questions in the BPVE field and possible future directions are discussed to inspire further investigations.