Vacuum-ultraviolet reflectance and photoemission study of the metal-insulator phase transitions in VO2, V6O13, and V2O3.
Vacuum-ultraviolet reflectance and photoemission study of the metal-insulator phase transitions in VO2, V6O13, and V2O3.
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DOI：
10.1103/physrevb.41.4993
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发表时间：
1990-03
期刊：
影响因子：
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通讯作者：
Shik Shin;S. Suga;M. Taniguchi;M. Fujisawa;H. Kanzaki;A. Fujimori;H. Daimon;Y. Ueda;K. Kosuge-K.-Kos
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文献类型：
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作者：
Shik Shin;S. Suga;M. Taniguchi;M. Fujisawa;H. Kanzaki;A. Fujimori;H. Daimon;Y. Ueda;K. Kosuge-K.-Kos
测量了VO{sub 2}， V{sub 2}O{sub 3}， V{sub 6}O{sub 13}和V{sub 2}O{sub 5}的真空紫外反射率和光电发射光谱，以研究3{ital d}波段结构和电子相关效应。在VO{sub 2}的情况下，通过金属绝缘体相变，在两个光谱中都发现了3{ital d} （{pi}{sup *}和{ital d}{sub {parallel}}）带结构的剧烈变化。金属VO{sub 2}的光发射光谱在费米能级上存在{pi}{sup *}和{ital d}{sub {parallel}}带，并且在{ital E}{sub {ital B}}=1.3 eV。在绝缘相位，光发射光谱中的{pi}{sup *}价带变为空带，反射光谱中的{pi}{sup *}导带上升约0.5 eV。这种相变带来的带移可能是VO{sub 2}金属-绝缘子转变的驱动力。在绝缘相位得到{ital d}{sub {parallel}}价与{pi}{sup *}导带之间的光学带隙为0.7 eV，其中{pi}{sup *}-{ital d}{sub {parallel}}相关能对该带隙有部分贡献。
Vacuum-ultraviolet reflectance and photoemission spectra of VO{sub 2}, V{sub 2}O{sub 3}, V{sub 6}O{sub 13}, and V{sub 2}O{sub 5} are measured in order to investigate the 3{ital d}-band structures and electron-correlation effects. In the case of VO{sub 2}, drastic changes in the 3{ital d} ({pi}{sup *} and {ital d}{sub {parallel}}) -band structures are found in both spectra through the metal-insulator phase transition. The {pi}{sup *} and {ital d}{sub {parallel}} bands are found at the Fermi level and {ital E}{sub {ital B}}=1.3 eV in the photoemission spectra of metallic VO{sub 2}. In the insulating phase, the {pi}{sup *} valence band in the photoemission spectra becomes empty and a rise of the {pi}{sup *} conduction band by about 0.5 eV is found in the reflectance spectra. This band shift through the phase transition may be a driving force of the metal-insulator transition of VO{sub 2}. The optical band gap between the {ital d}{sub {parallel}} valence and {pi}{sup *} conduction bands is obtained as 0.7 eV in the insulating phase, to which the {pi}{sup *}-{ital d}{sub {parallel}} correlation energy contributes partially.