State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
J Chem Phys. 2013 Nov 14;139(18):184706. doi: 10.1063/1.4828864.
Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.
类金刚石结构的铜基多元半导体是一类丰富的材料，它们在许多应用中具有广阔的前景。不幸的是，由于涉及到 Cu 的 d 电子，这些材料的电子性质的准确理论理解受到阻碍。基于密度泛函理论（DFT）的计算，使用局域密度近似或广义梯度近似通常会对这些材料的电子性质给出定性的错误，特别是对于窄带隙体系。已经证明，修正的 Becke-Johnson（mBJ）方法是一种很有前途的替代方法，如 GW 近似，用于快速的材料筛选和预测。然而，由于对局域化的 d 电子的处理不足，mBJ 方法直接应用于这些材料仍然会遇到很大的困难。我们表明，将 mBJ 势的优势与成熟的 DFT + U 方法的精神相结合，可以对电子结构进行更精确的描述，包括最具挑战性的窄带隙体系。用 mBJ + U 方法计算的大约 20 种铜基半导体的能带隙的调查表明，结果与可靠值的误差在±0.2eV 以内。
