arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.07433cond-mat.mtrl-sci
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Nonrad:从第一性原理计算非辐射俘获系数

Nonrad: Computing Nonradiative Capture Coefficients from First Principles

Mark E. Turiansky, Audrius Alkauskas, Manuel Engel, Georg Kresse, Darshana Wickramaratne, Jimmy-Xuan Shen, Cyrus E. Dreyer, Chris G. Van de Walle

摘要:

半导体晶体中的点缺陷为载流子提供了一种非辐射复合的方法。这种复合过程影响器件的性能。我们提出了Nonrad代码,该代码实现了Alkauskas等人的第一原理方法[Phys. Rev. B 90,075202(2014)],用于基于捕获过程的量子力学描述评估非辐射捕获系数。提出了一种在投影增广波理论中计算电声子耦合的方法。我们还表明,用高斯函数取代狄拉克δ函数的常见过程可以引入误差到所得的捕获率中,并实施另一种方案来适当地考虑振动加宽。最后,我们评估的准确性,使用解析近似的索末菲参数相比,直接数值计算。

英文摘要:

Point defects in semiconductor crystals provide a means for carriers to recombine nonradiatively. This recombination process impacts the performance of devices. We present the Nonrad code that implements the first-principles approach of Alkauskas et al. [Phys. Rev. B 90, 075202 (2014)] for the evaluation of nonradiative capture coefficients based on a quantum-mechanical description of the capture process. An approach for evaluating electron-phonon coupling within the projector augmented wave formalism is presented. We also show that the common procedure of replacing Dirac delta functions with Gaussians can introduce errors into the resulting capture rate, and implement an alternative scheme to properly account for vibrational broadening. Lastly, we assess the accuracy of using an analytic approximation to the Sommerfeld parameter by comparing with direct numerical evaluation.

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