Pressure-induced bcc to hcp transition in Fe: Magnetism-driven structure transformation
Pressure-induced bcc to hcp transition in Fe: Magnetism-driven structure transformation
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Fe 中压力诱导的 bcc 到 hcp 转变：磁驱动的结构转变
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
J. Minár
中科院分区：
文献类型：
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作者：
S. Mankovsky;S. Polesya;H. Ebert;W. Bensch;O. Mathon;S. Pascarelli;J. Minár
用从头计算方法研究了Fe中压致bcc → hcp相变。用无序局域矩（DLM）计算发现，温度引起的自旋涨落导致Burgers型晶格畸变能量的降低和横$N$点$TA_1$声子模的软化。ar{1}10]$极化。结果，系统中的自旋无序导致原子位移幅度的增加。另一方面，在我们的计算中得到的交换耦合参数强烈下降，在大幅度的晶格畸变。这导致结构自由度和磁自由度的相互关联，导致在有限温度下的压力下的体心立方结构的不稳定性。
The pressure induced bcc to hcp transition in Fe has been investigated via ab-initio electronic structure calculations. It is found by the disordered local moment (DLM) calculations that the temperature induced spin fluctuations result in the decrease of the energy of Burgers type lattice distortions and softening of the transverse $N$-point $TA_1$ phonon mode with $[ar{1}10]$ polarization. As a consequence, spin disorder in an system leads to the increase of the amplitude of atomic displacements. On the other hand, the exchange coupling parameters obtained in our calculations strongly decrease at large amplitude of lattice distortions. This results in a mutual interrelation of structural and magnetic degrees of freedom leading to the instability of the bcc structure under pressure at finite temperature.