多价态、多自旋态自由度的铁氧化物在压力的作用下会发生丰富的结构相变、自旋态转变及金属绝缘体转变。其中，自旋态转变与金属绝缘体转变或同时或相继发生，两转变的起因特别是自旋态转变对金属绝缘体转变的影响，一直是实验和理论研究中争论的焦点。. 本项目将选取地球上广泛存在的Mott型铁氧化物作为研究对象，结合遗传算法、第一性原理计算及模型计算，对其压力下自旋态转变对Mott转变的影响从以下几方面进行研究：（1）研究压力下体系的结构相变，明确各压力相的结构；（2）根据各压力相下的结构，研究带宽、关联等因素的变化，给出自旋态转变及金属绝缘体转变的相图；（3）研究自旋态转变对体系关联的影响，以及关联的改变与压力下带宽变化的相对强弱，从而确定自旋态转变对Mott转变的影响。以上研究将丰富人们对压力下Mott转变机理的认识，并为地球物理中铁氧化物压力下的行为提供参考。

The iron oxides exhibit abundant structural，spin-state and metal-insulator transitions under pressure， due to their multi-valence and spin-state degree of freedom. The spin-state and metal-insulator transitions occur simultaneously or successively. The origin of these two transitions, especially the influence of spin-state transition on metal-insulator transition has always been the focus of controversy in both experimental and theoretical studies.. In this project，we will investigate the pressure-induced behavior of Mott-type iron oxides which are widespread on earth, by combining genetic algorithms, first-principles calculations and model calculations. The influence of spin-state transition on Mott transition will be studied from the following aspects.(1)Investigate the pressure-induced structural transition and identify the structures at various pressure.(2) Based on these structures, explore the variations of bandwidth, correlation etc. and further demonstrate the phase diagram of spin-state and metal-insulator transitions.(3)Concern the influence of spin-state transition on the correlation and the relative intensity between the pressure-induced changes of bandwidth and correlation, to specify the influence of spin-state transition on the Mott transition. Our research will enrich the understanding of the pressure-induced Mott transition mechanism, and will provide reference for the geophysical study on the behavior of iron oxides under pressure.