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
We study Na2IrO3 by angle-resolved photoemission spectroscopy and in situ carrier doping via potassium deposition. From the K-induced chemical potential shift and the emergence of spectral weight across the insulating gap, together with complementary optical conductivity data, we estimate an optical gap Delta_eff=350 meV. By performing local-density approximation (LDA) band structure calculations, with the inclusion of spin-orbit coupling (SO) and Coulomb repulsion U, we determine that while the correct gap magnitude can only be reproduced by LDA+SO+U, the prodromes of an underlying insulating state are already found in LDA+SO. This challenges a simple Mott-Hubbard scenario, establishing Na2IrO3 as a spin-orbit-assisted antiferromagnetic insulator.
View original:
http://arxiv.org/abs/1204.4471
No comments:
Post a Comment