文章（APPLIED PHYSICS LETTERS 105, 053511 (2014)）使用密度泛函理论和密度泛函紧束缚近似研究了n-Si在方向电阻率下限的理想金属电子结构效应。结果表明，在高掺杂浓度时，“理想金属”假设在某些情况下会失效，因此对n-Si的接触电阻下限至少低估了一个数量级。金属和半导体在横向动量空间的失配，也就是所谓的“谷过滤效应”，对使用的原胞的横向边界情况的细节非常敏感。因此在金属－半导体接触面的电子输运的原子尺度模拟，需要明确所包含的金属原子和电子结构。
FIG. 1. Cross section structures and transverse momentum-resolved transmission spectra for epitaxial CoSi2 on  oriented Si. Part (a) is for the case of  oriented CoSi2 unit cell bound by the  and  directions lattice matched to a  oriented Si unit cell bound by the same orientations. Part (b) is for the case of  oriented CoSi2 unit cell bound by the [0-11] and  directions lattice matched to a  oriented Si unit cell bound by the same ori- entations. The transmission spectra are obtained at the Fermi Level for the metal and the semiconductor. The doping in Si is Nd 1⁄4 7 10 20 cm 3, the approxi- mate solid solubility limit of P in Si at annealing temperatures of over 950 C. Lightly colored spheres represent Si, while dark spheres represent Co atoms.
FIG. 2. Atomic structure and transverse momentum-resolved transmission spectra for the M-S interfaces formed by “coupling” CoSi2 and Si unit cells under the assumptions described above. Due to favorable overlapping of transverse momentum space, it can be seen that the epitaxial interface bounded by the  and  orientations leaves the transmission spectrum in Si unchanged from its own bulk limit. The interface bound by [0-11] and  orientations, how- ever, results in the complete filtering out four out of six Si valleys due to poor overlap between the transverse momentum space of CoSi2 and Si for this unit cell orientation as shown in Figure 1.