Range-separated hybrid functionals for accurate prediction of band gaps of extended systems

In this work, we systematically evaluate the accuracy in band gap prediction of range-separated hybrid functionals on a large set of semiconducting and insulating materials and carry out comparisons with the performance of their global counterparts. We observe that all the range-separated hybrid functionals that correctly describe the long-range dielectric screening significantly improve from standard hybrid functionals such as PBE0 and HSE06. Among this group, the choice of the short-range Fock exchange fraction and the screening length can further reduce the predicted error. We then propose a universal expression for the selection of the inverse screening parameter as a function of the short-range and long-range Fock exchange fractions, which results in a mean absolute error as small as 0.15 eV for band gap prediction.

在本项研究中，我们对范围分离混合泛函在大量半导体和绝缘材料中带隙预测的准确性进行了系统评估，并与它们的全局对应泛函的性能进行了比较。观察发现，所有能够正确描述长程介电屏蔽效应的范围分离混合泛函相较于标准混合泛函如PBE0和HSE06均有显著提升。在此类泛函中，短程福克交换分数和屏蔽长度的选择能够进一步降低预测误差。随后，我们提出了一种关于选择逆屏蔽参数的通用表达式，该表达式以短程和长程福克交换分数为函数，从而实现了带隙预测的平均绝对误差低至0.15 eV。