Switching of Conducting Planes by Partial Dimer Formation in IrTe$_2$
  Single-crystal X-ray diffraction was employed to study the structural-electronic phase transition of IrTe$_2$ at approximately 270 K. The low-temperature structure was found to be a triclinic (space group $P\bar{1}$) characterized by the partial formation of Ir$_2$ dimers in the triangular lattice of IrTe$_2$, resulting in a structural modulation with a wave vector of ${\bf q} = (1/5, 0, -1/5)$. First-principles band calculations demonstrate that tilted two-dimensional Fermi surfaces emerge in the triclinic phase, suggesting that switching of the conducting planes occurs from the basal plane of the trigonal IrTe$_2$ to the tilted plane normal to ${\bf q}$ of the triclinic IrTe$_2$. 
Tatsuya Toriyama, Masao Kobori, Takehisa Konishi, Yukinori Ohta,   Kunihisa Sugimoto, Jungeun Kim, Akihiko Fujiwara, Sunseng...
cond-mat.str-el cond-mat.mtrl-sci cond-mat.supr-con