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钙钛矿锰氧化物(以下简称锰氧化物,如La_(1-x)Sr_xMnO_3等,x为掺杂浓度)因其优异的电、磁性质受到人们广泛的关注,但是对于其材料内部载流子性质的认识至今仍没有统一定论.本文基于锰氧化物内Mn—O链的特点,建立一维紧束缚模型,对锰氧化物载流子的性质展开研究.发现在掺杂浓度x=0.5时,系统处于铁磁态,自旋能级完全劈裂,价带和导带之间存在带隙,所有电子态呈现扩展行为.进一步掺杂,将出现局域电子态,同时伴随着晶格的局域畸变,形成所谓的极化子.伴随着极化子的出现,带隙中出现极化子深能级.极化子携带的电荷量越多,形成的晶格缺陷越深,局域能级也越深.当极化子的电荷量继续增加时,极化子解离,载流子倾向于形成能量更低的正反“孤子”对.
Perovskite manganese oxide (hereinafter referred to as manganese oxide, such as La_ (1-x) Sr_xMnO_3, etc., x is the doping concentration) due to its excellent electrical and magnetic properties have received widespread attention, but for its material flow However, there is still no unified conclusion on the nature of the sub-species.In this paper, based on the characteristics of Mn-O chains in manganese oxide, a one-dimensional tight binding model was established to study the properties of manganese oxide carriers.It was found that when the doping concentration x = 0.5 , The system is in the ferromagnetic state, the spin level is completely cleaved, and the bandgap exists between the valence band and the conduction band, and all the electronic states show the spreading behavior.With further doping, the local electronic states will appear along with the lattice Of the local distortion, the formation of the so-called polaron.With the emergence of polaron, the bandgap polaron level appears.Polarize the charge carried by more, the deeper the lattice defects formed, Bureau When the charge of the polaron continues to increase, the polaron dissociates and the charge carriers tend to form a less energetic positive and negative “soliton” pair.