Zhou Fei, Maxisch Thomas, Ceder Gerbrand
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2006 Oct 13;97(15):155704. doi: 10.1103/PhysRevLett.97.155704.
We demonstrate that configurational electronic entropy, previously neglected, in ab initio thermodynamics of materials can qualitatively modify the finite-temperature phase stability of mixed-valence oxides. While transformations from low-T ordered or immiscible states are almost always driven by configurational disorder (i.e., random occupation of lattice sites by multiple species), in FePO4-LiFePO4 the formation of a solid solution is almost entirely driven by electronic rather than ionic configurational entropy. We argue that such an electronic entropic mechanism may be relevant to most other mixed-valence systems.
我们证明，在材料的从头算热力学中，先前被忽视的构型电子熵能够定性地改变混合价氧化物的有限温度相稳定性。虽然从低温有序或不混溶状态的转变几乎总是由构型无序驱动（即多种物种随机占据晶格位点），但在磷酸铁锂（FePO4-LiFePO4）中，固溶体的形成几乎完全由电子而非离子构型熵驱动。我们认为，这种电子熵机制可能与大多数其他混合价体系相关。
