Hard X-ray core-level photoemission of V2O3
Hard X-ray core-level photoemission of V2O3
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DOI：
10.1209/epl/i2004-10240-4
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发表时间：
2004-11
期刊：
影响因子：
1.8
通讯作者：
N. Kamakura;M. Taguchi;A. Chainani;Y. Takata;K. Horiba;K. Yamamoto;K. Tamasaku;Y. Nishino;D. Miwa;E. Ikenaga;M. Awaji;A. Takeuchi;H. Ohashi;Y. Senba;H. Namatame;M. Taniguchi;T. Ishikawa;Keisuke L. I. Kobayashi;Shik Shin
中科院分区：
文献类型：
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作者：
N. Kamakura;M. Taguchi;A. Chainani;Y. Takata;K. Horiba;K. Yamamoto;K. Tamasaku;Y. Nishino;D. Miwa;E. Ikenaga;M. Awaji;A. Takeuchi;H. Ohashi;Y. Senba;H. Namatame;M. Taniguchi;T. Ishikawa;Keisuke L. I. Kobayashi;Shik Shin
利用硬X射线（HX：hν = 5940 eV）芯能级光电子能谱（PES）研究了V2 O3单晶的Mott-Hubbard金属-绝缘体转变. HX-PES能够在顺磁金属和反铁磁绝缘相的电子结构的散装探针。金属V2 O3在低结合能下显示出与V 1 s、2 p和3s核心能级主峰的额外特征，这些核心能级在绝缘相中消失。使用软X射线（SX：hν = 1450 eV）也观察到金属相中的低结合能特征，但与HX-PES光谱相比具有降低的相对强度。一个模型集群计算，包括核心空穴屏蔽相干态在费米能级，再现金属相的低结合能功能。O 1 s芯能级也显示出光谱变化：金属相中的不对称线形转变为绝缘相中的对称线形，与金属-绝缘体转变一致。结果表明，相干态屏蔽在体中比在表面更有效。因此，HX-PES是强关联电子系统中金属-绝缘体转变的电子结构变化的可靠探针。
We study the Mott-Hubbard metal-insulator transition in single-crystal V2O3 using hard X-ray (HX: hν = 5940 eV) core-level photoemission spectroscopy (PES). HX-PES enables a bulk probe of the electronic structure in the paramagnetic metallic and antiferromagnetic insulating phases. Metallic V2O3 shows additional features at low binding energy to the main peak of V 1s, 2p, and 3s core levels, which vanish in the insulating phase. The low-binding-energy features in the metallic phase are also observed using soft X-rays (SX: hν = 1450 eV), but with a reduced relative intensity compared to the HX-PES spectrum. A model cluster calculation including core hole screening by coherent states at the Fermi level, reproduces the low-binding-energy features in the metallic phase. The O 1s core level also shows spectral changes: the asymmetric line shape in the metallic phase transforms to a symmetric line shape in the insulating phase, consistent with the metal-insulator transition. The results indicate screening by coherent states is more effective in the bulk compared to the surface. HX-PES is, thus, a reliable probe of the electronic-structure changes across the metal-insulator transition in strongly correlated electron systems.