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Temperature dependent electron-phonon spectral function and the intrinsic resistivity of a metal: A case study of monolayer Ti2N
Physical Review B ( IF 3.7 ) Pub Date : 
Binyuan Zhang, Mingfeng Zhu, Zhe Liu, Fei Guo, Yisong Zheng

The transport spectral function of electron-phonon(e-ph) interaction in the double delta function approximation(DDFA) is extensively employed to calculate the intrinsic resistivity(arising from e-ph scattering) of metallic materials in recently works of first principles calculations. In contrast, a more fundamental transport spectral function with Fermi smearing effect due to finite temperature(T) and nonzero phonon frequency is less involved. In this work, we perform first-principles calculations of the intrinsic resistivity of $\rm{Ti_2N}$ monolayer, a potential MXene material, by employing the two kinds of spectral function. We find that the spectral function with the DDFA fails to describe correctly the temperature dependence of the intrinsic resistivity of $\rm{Ti_2N}$ monolayer at T>250 K, much lower than the Debye temperature. The underlying reason is that $\rm{Ti_2N}$ monolayer has multi-sheet Fermi surface formed by several bands. And some band edges are very close to the Fermi surface. Our results suggest that the transport spectral function with Fermi smearing effect, instead of the one with the DDFA, is always adequate for studying the intrinsic resistivity of realistic materials on the level of first-principles calculations. In addition, we give a brief remark on the intrinsic resistivity of $\rm{Ti_2N}$ monolayer, in contrast with other typical two-dimensional materials, which is significant from the viewpoint of application of such a MXene material.

中文翻译:

温度相关的电子声子光谱函数和金属的固有电阻率:以单层Ti2N为例

电子声子的传输谱函数Ë双德尔塔函数近似(DDFA)中的-ph)相互作用被广泛用于计算本征电阻率(从 Ë-ph散射)在第一性原理计算的最新著作中。相反,由于有限的温度,具有费米拖尾效应的更基本的传输谱函数(Ť)和非零声子频率较少涉及。在这项工作中,我们通过使用两种光谱函数,对潜在的MXene材料$ \ rm {Ti_2N} $单层的本征电阻率进行第一性原理计算。我们发现具有DDFA的光谱函数未能正确描述$ \ rm {Ti_2N} $单层本征电阻率在温度下的温度依赖性Ť>250K,远低于德拜温度。根本原因是$ \ rm {Ti_2N} $单层具有由多个能带形成的多片费米表面。并且一些带的边缘非常靠近费米表面。我们的结果表明,具有费米拖尾效应的传输谱函数(而不是具有DDFA的函数)始终足以在第一性原理计算的水平上研究实际材料的固有电阻率。此外,与其他典型的二维材料相比,我们对$ \ rm {Ti_2N} $单层的本征电阻率作了简要说明,这对于此类MXene材料的应用而言意义重大。
更新日期:2020-09-21
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