1203.2411 (D. Ootsuki et al.)

Orbital Degeneracy and Peierls Instability in Triangular Lattice
Superconductor Ir$_{1-x}$Pt$_x$Te$_2$    [PDF]

D. Ootsuki, Y. Wakisaka, S. Pyon, K. Kudo, M. Nohara, M. Arita, H. Anzai, H. Namatame, M. Taniguchi, N. L. Saini, T. Mizokawa

We have studied electronic structure of triangular lattice Ir$_{1-x}$Pt$_x$Te$_2$ superconductor using photoemission spectroscopy and model calculations. Ir $4f$ core-level photoemission spectra show that Ir $5d$ $t_{2g}$ charge modulation established in the low temperature phase of IrTe$_2$ is suppressed by Pt doping. This observation indicates that the suppression of charge modulation is related to the emergence of superconductivity. Valence-band photoemission spectra of IrTe$_2$ suggest that the Ir $5d$ charge modulation is accompanied by Ir $5d$ orbital reconstruction. Based on the photoemission results and model calculations, we argue that the orbitally-induced Peierls effect governs the charge and orbital instability in the Ir$_{1-x}$Pt$_x$Te$_2$.

View original: http://arxiv.org/abs/1203.2411