Electrodynamics of the vanadium oxides VO2 and V2O3
Electrodynamics of the vanadium oxides VO2 and V2O3
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DOI：
10.1103/physrevb.77.115121
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发表时间：
2008-03-01
影响因子：
3.7
通讯作者：
Basov, D. N.
中科院分区：
文献类型：
--
作者：
Qazilbash, M. M.;Schafgans, A. A.;Basov, D. N.
采用椭圆偏振法和近垂直入射反射法研究了二氧化钒（VO 2）和三氧化二钒（V2 O3）薄膜在远红外和紫外波段的光学和红外特性。显著的变化发生在VO 2和V2 O3的光学电导率跨越金属-绝缘体过渡至少高达（并可能超过）6 eV。我们认为，这种变化在很宽的频率范围内的光学电导率和电子光谱重量的重要作用，这些钒氧化物的金属-绝缘体过渡的电子相关性的证据。我们观察到一个尖锐的光学过渡与可能的最终状态（激子）的绝缘相VO 2的效果。这种急剧的光学跃迁发生在由钒二聚体的准一维链产生的窄a（1g）带之间。在金属相的VO 2和V2 O3的电子相关性导致减少的电荷载流子的动能相比，带理论值，与顺磁性金属V2 O3相比，金红石金属VO 2显示出更强的相关性的证据。
The optical and infrared properties of films of vanadium dioxide (VO2) and vanadium sesquioxide (V2O3) have been investigated via ellipsometry and near-normal incidence reflectance measurements from far infrared to ultraviolet frequencies. Significant changes occur in the optical conductivity of both VO2 and V2O3 across the metal-insulator transitions at least up to (and possibly beyond) 6 eV. We argue that such changes in optical conductivity and electronic spectral weight over a broad frequency range are evidence of the important role of electronic correlations to the metal-insulator transitions in both of these vanadium oxides. We observe a sharp optical transition with possible final state (exciton) effects in the insulating phase of VO2. This sharp optical transition occurs between narrow a(1g) bands that arise from the quasi-one-dimensional chains of vanadium dimers. Electronic correlations in the metallic phases of both VO2 and V2O3 lead to reduction of the kinetic energy of the charge carriers compared to band theory values, with paramagnetic metallic V2O3 showing evidence of stronger correlations compared to rutile metallic VO2.