Density-functional theory for fluid-solid and solid-solid phase transitions

被引:10
|
作者
Bharadwaj, Atul S. [1 ]
Singh, Yashwant [1 ]
机构
[1] Banaras Hindu Univ, Dept Phys, Varanasi 221005, Uttar Pradesh, India
关键词
SYSTEMS;
D O I
10.1103/PhysRevE.95.032120
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
We develop a theory to describe solid-solid phase transitions. The density functional formalism of classical statistical mechanics is used to find an exact expression for the difference in the grand thermodynamic potentials of the two coexisting phases. The expression involves both the symmetry conserving and the symmetry broken parts of the direct pair correlation function. The theory is used to calculate phase diagram of systems of soft spheres interacting via inverse power potentials u(r) = epsilon (sigma/r)(n),where parameter n measures softness of the potential. We find that for 1/n < 0.154 systems freeze into the face centered cubic (fcc) structure while for 1/n >= 0.154 the body-centred-cubic (bcc) structure is preferred. The bcc structure transforms into the fcc structure upon increasing the density. The calculated phase diagram is in good agreement with the one found from molecular simulations.
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页数:8
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