arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.05186cond-mat.mtrl-sci
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高温金属中的电子-声子耦合

Electron-phonon coupling in metals at high electronic temperatures

N. Medvedev, I. Milov

摘要:

电子-声子耦合是超快能量沉积后控制材料演化的重要参数之一,也是目前尚未被研究的一个重要参数。本文应用动力学耦合方法计算了电子温度高于原子温度的非平衡固体中的非绝热电子-离子能量交换。它被实现到紧束缚分子动力学代码中,并用于研究各种元素金属中的电子-声子耦合。所开发的方法是一个通用的计划,适用于电子温度高达几个电子伏特,并任意原子的配置和动力学。我们证明,计算的电子-离子(电子-声子)耦合参数与现有的实验数据在高电子温度制度,验证了模型。在此研究了以下材料-面心立方金属:Al、Ca、Ni、Cu、Sr、Y、Zr、Rh、Pd、Ag、Ir、Pt、Au、Pb;六方心立方金属:Mg、Sc、Ti、Co、Zn、Tc、Ru、Cd、Hf、Re、Os;体心立方金属:V、Cr、Fe、Nb、Mo、Ba、Ta、W;金刚石立方晶格金属:Sn; Ga、In、Mn、Te和Se的特定情况;以及另外的半金属石墨和半导体Si和Ge。对于许多材料,我们提供了第一个也是迄今为止唯一的估计,电子-声子耦合在电子温度升高,可用于各种模型模拟超快能量沉积的物质。我们还讨论了耦合参数与原子质量、温度和密度的关系。

英文摘要:

Electron-phonon coupling, being one of the most important parameters governing the material evolution after ultrafast energy deposition, yet remains the most unexplored one. In this work, we applied the dynamical coupling approach to calculate the nonadiabatic electron-ion energy exchange in nonequilibrium solids with the electronic temperature high above the atomic one. It was implemented into the tight-binding molecular dynamics code, and used to study electron-phonon coupling in various elemental metals. The developed approach is a universal scheme applicable to electronic temperatures up to a few electron-Volts, and to arbitrary atomic configuration and dynamics. We demonstrate that the calculated electron-ion (electron-phonon) coupling parameter agrees well with the available experimental data in high-electronic-temperature regime, validating the model. The following materials are studied here - fcc metals: Al, Ca, Ni, Cu, Sr, Y, Zr, Rh, Pd, Ag, Ir, Pt, Au, Pb; hcp metals: Mg, Sc, Ti, Co, Zn, Tc, Ru, Cd, Hf, Re, Os; bcc metals: V, Cr, Fe, Nb, Mo, Ba, Ta, W; diamond cubic lattice metals: Sn; specific cases of Ga, In, Mn, Te and Se; and additionally semimetal graphite and semiconductors Si and Ge. For many materials, we provide the first and so far the only estimation of the electron-phonon coupling at elevated electron temperatures, which can be used in various models simulating ultrafast energy deposition in matter. We also discuss the dependence of the coupling parameter on the atomic mass, temperature and density.

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