Biaxial strain effect induced electronic structure alternation and trimeron recombination in Fe(3)O(4).
Biaxial strain effect induced electronic structure alternation and trimeron recombination in Fe(3)O(4).
复制标题
双轴应变效应诱导 Fe3O4 中的电子结构交替和三聚体重组
DOI：
10.1038/srep43403
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发表时间：
2017-02-23
影响因子：
4.6
通讯作者：
Mi W
中科院分区：
文献类型：
--
作者：
Liu X;Yin L;Mi W
Fe_3O_4的Verwey转变是由电荷有序化引起的第一个金属-绝缘体转变。然而，Verwey转变的物理机制和影响因素仍存在争议。据此，采用第一性原理计算方法研究了应变对P2/candCc对称低温相Fe 3 O 4电子结构的影响.每个空间群的LTP Fe 3 O 4都有一个临界应变。在P2/c下，Fe 3 O 4对压应变敏感，而对Cc的拉应变敏感。在临界区，具有两种对称性的LTP Fe_3O_4的带隙随应变线性增加。当应变超过临界值时，自旋下降的t2 g电子在Fe（B4）（P2/c）和Fe（B42）（Cc）上的态密度在x ~ 2-y ~ 2和dxz +dyz之间变化。CC中出现的三聚体受菌株的影响。在压应变下，三聚体沿轴向的相关性增强，但沿沿着面对角线的相关性减弱，而在拉应变下则相反。结果表明，Fe_3O_4的电子结构可以通过应变进行调谐.较窄或较宽的带隙意味着较低或较高的转变温度比它的本体没有应变，这也给了一个一瞥的电荷轨道有序的Fe 3 O 4的起源。
The Verwey transition in Fe3O4is the first metal-insulator transition caused by charge ordering. However, the physical mechanism and influence factors of Verwey transition are still debated. Herewith, the strain effects on the electronic structure of low-temperature phase (LTP) Fe3O4withP2/candCcsymmetries are investigated by first-principles calculations. LTP Fe3O4with each space group has a critical strain. WithP2/c, Fe3O4is sensitive to the compressive strain, but it is sensitive to tensile strain forCc. In the critical region, the band gap of LTP Fe3O4with both two symmetries linearly increases with strain. When strain exceeds the critical value, DOS of spin-downt2gelectron at Fe(B4) withP2/cand Fe(B42) withCcchanges betweendx2-y2 anddxz+dyz. The trimerons appear inCccan be affected by strain. With a compressive strain, the correlation of trimeron alongxandyaxes is strengthened, but broken along the face diagonal of FeB4O4, which is opposite at the tensile strains. The results suggest that the electronic structure of Fe3O4is tunable by strain. The narrower or wider band gap implies a lower or higher transition temperature than its bulk without strains, which also gives a glimpse of the origin of charge-orbital ordering in Fe3O4.