Superioniclike Diffusion in an Elemental Crystal: bcc Titanium.
Superioniclike Diffusion in an Elemental Crystal: bcc Titanium.
复制标题
DOI：
10.1103/physrevlett.123.105501
复制
发表时间：
2019-06
影响因子：
8.6
通讯作者：
D. Sangiovanni;D. Sangiovanni;J. Klarbring;D. Smirnova;D. Smirnova;N. Skripnyak;D. Gambino;M. Mrovec;S. Simak;I. Abrikosov
中科院分区：
文献类型：
--
作者：
D. Sangiovanni;D. Sangiovanni;J. Klarbring;D. Smirnova;D. Smirnova;N. Skripnyak;D. Gambino;M. Mrovec;S. Simak;I. Abrikosov
解析：A。B. Belonoshko等人。地球物理学报，12 (2)(2017)1752-089410.1038/ngeo2892]揭示了bcc Fe中几个原子在内核温度和压力下协同迁移的发生。在这里，我们将第一性原理和半经验原子模拟结合起来，表明类似于在极端条件下预测的bcc铁的扩散机制也是有效的，并且与纯Ti在环境压力下的高温bcc相相关。该机制需要在无缺陷的晶体区域中，沿着纠缠的闭环路径进行大量（从两个到几十个）邻居的快速集体运动。我们认为这种现象与超电子学和液态金属的扩散行为非常相似。此外，我们认为协同迁移是先前通过中子散射检测到的极小ω模声子频率的原子表现，以及bcc Ti异常大且明显非arrhenius自扩散特性的机制。
Recent theoretical investigations [A. B. Belonoshko et al. Nat. Geosci. 10, 312 (2017)1752-089410.1038/ngeo2892] revealed the occurrence of the concerted migration of several atoms in bcc Fe at inner-core temperatures and pressures. Here, we combine first-principles and semiempirical atomistic simulations to show that a diffusion mechanism analogous to the one predicted for bcc iron at extreme conditions is also operative and of relevance for the high-temperature bcc phase of pure Ti at ambient pressure. The mechanism entails a rapid collective movement of numerous (from two to dozens) neighbors along tangled closed-loop paths in defect-free crystal regions. We argue that this phenomenon closely resembles the diffusion behavior of superionics and liquid metals. Furthermore, we suggest that concerted migration is the atomistic manifestation of vanishingly small ω-mode phonon frequencies previously detected via neutron scattering and the mechanism underlying anomalously large and markedly non-Arrhenius self-diffusivities characteristic of bcc Ti.