Bulk band gaps in divalent hexaborides.
Bulk band gaps in divalent hexaborides.
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DOI：
10.1103/physrevlett.89.157601
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发表时间：
2001-07
影响因子：
8.6
通讯作者：
J. Denlinger;Jules A. Clack;J. Allen;G. Gweon;D. M. Poirier;C. G. Olson;J. Sarrao;A. Bianchi
中科院分区：
文献类型：
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作者：
J. Denlinger;Jules A. Clack;J. Allen;G. Gweon;D. M. Poirier;C. G. Olson;J. Sarrao;A. Bianchi
二价六硼化物的互补角分辨光电子能谱和体敏k分辨共振非弹性x射线散射揭示了价带和导带之间存在一个>；1 eV的X点能隙，这与几种新的铁磁性模型中假定的能带重叠相反。这种半导体带隙意味着在输运测量中检测到的载流子来自缺陷，而在导带底部测量到的体费米能级的位置意味着硼空位是多余电子的来源。测量到的CaB6的能带结构和X点能隙为多体准粒子能带计算提供了严格的测试条件。
Complementary angle-resolved photoemission and bulk-sensitive k-resolved resonant inelastic x-ray scattering of divalent hexaborides reveal a >1 eV X-point gap between the valence and conduction bands, in contradiction to the band overlap assumed in several models of their novel ferromagnetism. This semiconducting gap implies that carriers detected in transport measurements arise from defects, and the measured location of the bulk Fermi level at the bottom of the conduction band implicates boron vacancies as the origin of the excess electrons. The measured band structure and X-point gap in CaB6 additionally provide a stringent test case for many-body quasiparticle band calculations.