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arXiv 1204.4471cond-mat.str-elcond-mat.supr-con
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具有340 meV带隙的自旋轨道辅助反铁磁绝缘体Na2IrO3

Na2IrO3 as a spin-orbit-assisted antiferromagnetic insulator with a 340 meV gap

R. Comin, G. Levy, B. Ludbrook, Z. -H. Zhu, C. N. Veenstra, J. A. Rosen, Yogesh Singh, P. Gegenwart, D. Stricker, J. N. Hancock, D. van der Marel, I. S. Elfimov, A. Damascelli

摘要:

本文采用ARPES、光学和局域密度近似(LDA)下的能带结构计算方法对Na 2 IrO 3进行了研究。Ir 5d-t2 g流形的弱色散突出了结构扭曲和自旋轨道耦合(SO)在驱动系统更接近莫特转变中的重要性。我们探测到一个绝缘能隙Δ_gap = 340 meV,它在300 K时已经打开,即使在T_N ~ 15 K时也没有明显的温度依赖性,这与Slater型描述不同。包含SO和库仑排斥U的LDA分析表明,虽然在LDA+SO中已经发现了潜在的绝缘态,但正确的能隙大小只能由LDA+SO+U再现,其中U = 3 eV。这确立了Na 2 IrO 3作为一种新型的莫特相关绝缘体,其中库仑效应和相对论效应必须平等对待。

英文摘要:

We study Na2IrO3 by ARPES, optics, and band structure calculations in the local-density approximation (LDA). The weak dispersion of the Ir 5d-t2g manifold highlights the importance of structural distortions and spin-orbit coupling (SO) in driving the system closer to a Mott transition. We detect an insulating gap Δ_gap = 340 meV which, at variance with a Slater-type description, is already open at 300 K and does not show significant temperature dependence even across T_N ~ 15 K. An LDA analysis with the inclusion of SO and Coulomb repulsion U reveals that, while the prodromes of an underlying insulating state are already found in LDA+SO, the correct gap magnitude can only be reproduced by LDA+SO+U, with U = 3 eV. This establishes Na2IrO3 as a novel type of Mott-like correlated insulator in which Coulomb and relativistic effects have to be treated on an equal footing.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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