Electronic structure reconstruction by orbital symmetry breaking in   IrTe2
  We report an angle-resolved photoemission spectroscopy (ARPES) study on IrTe2 which exhibits an interesting lattice distortion below 270 K and becomes triangular lattice superconductors by suppressing the distortion via chemical substitution or intercalation. ARPES results at 300 K show multi-band Fermi surfaces with six-fold symmetry which are basically consistent with band structure calculations. At 20 K in the distorted phase, whereas the flower shape of the outermost Fermi surface does not change from that at 300 K, topology of the inner Fermi surfaces is strongly modified by the lattice distortion. The Fermi surface reconstruction by the distortion depends on the orbital character of the Fermi surfaces, suggesting importance of Ir 5d and/or Te 5p orbital symmetry breaking. 
D. Ootsuki, S. Pyon, K. Kudo, M. Nohara, M. Horio, T. Yoshida, A.   Fujimori, M. Arita, H. Anzai, H. Namatame, M. Taniguchi,...
cond-mat.supr-con cond-mat.str-el