A new method for development of bond-order potentials for transition bcc metals
A new method for development of bond-order potentials for transition bcc metals
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DOI：
10.1088/0965-0393/22/3/034002
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发表时间：
2014-04
影响因子：
1.8
通讯作者：
Yi-Shen Lin;M. Mrovec;V. Vitek
中科院分区：
文献类型：
--
作者：
Yi-Shen Lin;M. Mrovec;V. Vitek
介绍了非磁性过渡金属V、Nb、Ta、Cr、Mo和W的键序势数值计算的新进展。设置防喷器的原则与早期开发相同(Aoki et al . 2007 Prog。板牙。科学学报（自然科学版）。然而，键积分是基于DFT计算中最近先进的紧密结合参数化方法（Madsen et al . 2011 Phys.）。中国生物医学工程学报（英文版），2011。Rev. B 84 155119)，不需要任何筛选。同时，环境依赖斥力的功能形式与Aoki和Kurokawa （2007 J. Phys）提出的氩中s和p电子重叠产生的斥力的功能形式相一致。:提供者。物质19 136228)。环境依赖斥力的相同物理起源证明了这一点，在过渡金属中，这种斥力是由在强共价键的影响下被挤进离子核心区域的s电子重叠引起的。开发的BOPs的测试包括研究替代高能量结构、bcc结构通过连续畸变构型与其他结构连接的转变路径、空位形成能的评估和声子谱的计算。在所有情况下，防喷器计算与DFT计算和/或现有实验数据的一致性都非常令人满意。{1 0 1}面的γ-面均表明过渡金属中1/2 < 1 1 1 1 >螺位错的核是非简并的。这也与现有的计算完全一致，这些计算充分解释了d电子的量子力学性质，d电子在过渡金属中提供了大量的键合。开发的BOPs的测试清楚地表明，它们可以转移到理想bcc晶格范围之外的结构中，并且适合于研究扩展晶体缺陷的原子结构和行为。
A new development of numerical bond-order potentials (BOPs) for the non-magnetic transition metals V, Nb, Ta, Cr, Mo and W is presented. The principles on which the BOPs have been set up are the same as in earlier developments (Aoki et al 2007 Prog. Mater. Sci. 52 154). However, the bond integrals are based on the recently advanced method of parametrization of tight-binding from DFT calculations (Madsen et al 2011 Phys. Rev. B 83 4119, Urban et al 2011 Phys. Rev. B 84 155119) and do not require any screening. At the same time, the functional form of the environmentally dependent repulsion is identified with the functional form of the repulsion arising from the overlap of s and p electrons in argon as proposed in Aoki and Kurokawa (2007 J. Phys.: Condens. Matter 19 136228). This is justified by the same physical origin of the environment dependent repulsion, which in transition metals arises from the overlap of s electrons that are being squeezed into the ion core regions under the influence of the strong covalent d bonds. The testing of the developed BOPs involves investigation of alternative higher energy structures, transformation paths connecting the bcc structure with other structures via continuously distorted configurations, evaluation of the vacancy formation energy and calculation of phonon spectra. In all cases, the BOP calculations are in more than satisfactory agreement with either DFT calculations and/or available experimental data. The calculated γ-surfaces for {1 0 1} planes all suggest that the core of 1/2〈1 1 1〉 screw dislocations is non-degenerate in the transition metals. This is also in full agreement with available calculations that account fully for the quantum-mechanical nature of the d electrons that provide the bulk of the bonding in transition metals. The testing of developed BOPs clearly demonstrates that they are transferable to structures well outside the regime of the ideal bcc lattice and are suitable for investigating the atomic structure and behaviour of extended crystal defects.