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 IrTe₂ at approximately 270 K. The lowerature structure was found to be a triclinic (space group P1̄) characterized by the partial formation of Ir₂ dimers in the triangular lattice of IrTe₂, resulting in a structural modulation with a wave vector of 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 IrTe₂ to the tilted plane normal to q of the triclinic IrTe₂.