Angle-resolved photoemission study of Nb-doped SrTiO3
Angle-resolved photoemission study of Nb-doped SrTiO3
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DOI：
10.1103/physrevb.79.113103
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发表时间：
2009-03
影响因子：
3.7
通讯作者：
M. Takizawa;K. Maekawa;H. Wadati;T. Yoshida;A. Fujimori;H. Kumigashira;M. Oshima
中科院分区：
文献类型：
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作者：
M. Takizawa;K. Maekawa;H. Wadati;T. Yoshida;A. Fujimori;H. Kumigashira;M. Oshima
用角分辨光电子能谱（ARPES）研究了Nb掺杂的带绝缘体的价带结构。我们发现，在[k=（πa，πa，0）]和[k=（πa，πa，πa）]点的价带顶处的ARPES谱从费米能级以下开始，与间接带隙3.3eV和导带底位置一致。然而，ARPES谱的峰位从3.3eV阈值向更高的结合能移动。由于在和点的带具有纯的特性，我们将这种位移归因于氧空穴与光学声子的强耦合，类似于在各种过渡金属氧化物中观察到的电子光电子能谱的峰位移。
We have performed an angle-resolved photoemission spectroscopy (ARPES) study of thevalence-band structure of Nb-doped, in which a dilute concentration of electrons are doped into theband insulator. We have found that ARPES spectra at the valence-band maxima at the[k=( πa , πa ,0)] and[k=( πa , πa , πa )] points start frombelow the Fermi level, consistent with the indirect band gap of 3.3 eV and theposition at the bottom of the conduction band. The peak position of the ARPES spectra were, however, shifted toward higher binding energies byfrom the 3.3 eV threshold. Because the bands at theandpoints have purecharacter, we attribute thisshift to strong coupling of the oxygenhole with optical phonons, in analogy with the peak shifts observed for-electron photoemission spectra in various transition-metal oxides.