Collective excitations in Na2IrO3
Collective excitations in Na2IrO3
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Na2IrO3 中的集体激发
DOI：
10.1088/0953-8984/28/2/026006
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Jun-ichi Igarashi and Tatsuya Nagao
中科院分区：
文献类型：
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作者：
S. Nakamura;T. Sakakibara;Y. Shimzu;S. Kittaka;Y. Kono;Y. Haga;J. Pospisil;and E. Yamamoto.;Jun-ichi Igarashi and Tatsuya Nagao
用巡游电子方法研究了Na 2 IrO 3的集体激发.我们考虑了一个多轨道紧束缚模型，其中Ir 5d态之间的电子转移是通过氧2 p态介导的，而d-d直接转移是在蜂窝晶格上进行的。在Hartree-Fock近似下，研究了单电子能量和基态能量。当直接d-d转移较弱时，由于准分子轨道的形成，我们得到了几乎平坦的能带，基态呈现锯齿形自旋序。在随机相位近似下的密度-密度相关函数的评估表明，集体激发出现的束缚态。对于一个适当的d-d直接转移值，它们中的一部分集中在能区
We study the collective excitations of Na 2 IrO 3 in an itinerant electron approach. We consider a multi-orbital tight-binding model with the electron transfer between the Ir 5d states mediated via oxygen 2p states and the direct d–d transfer on a honeycomb lattice. The one-electron energy as well as the ground state energy are investigated within the Hartree–Fock approximation. When the direct d–d transfer is weak, we obtain nearly flat energy bands due to the formation of quasimolecular orbitals, and the ground state exhibits the zigzag spin order. The evaluation of the density–density correlation function within the random phase approximation shows that the collective excitations emerge as bound states. For an appropriate value of the direct d–d transfer, some of them are concentrated in the energy region