Honeycomb lattice type charge density wave associated with interlayer Cu ions ordering in 1T−CuxTiSe2
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The phase transition phenomenon in a semimetallic 1T−TiSe2 has attracted attention as an excitonic insulator. However, as the phase transition accompanying superlattice peaks has the q vector connecting the Fermi surfaces of the three-dimensional shape of hole and electron pockets, it also assumes the charge density wave (CDW) state owing to the electron–phonon interaction. To understand the electronic state at the low temperature, control of the chemical potential was attempted by electronic doping through Cu^+ intercalation. Physical properties measurements and synchrotron x-ray diffraction experiments in CuxTiSe2 (x=0–0.35) were performed. The phase transition was determined to occur as a cooperative phenomenon between the honeycomb lattice type CDW corresponding to the nesting vector and the ordered state of the Cu^+ ions between TiSe2 layers at a specific doping amount (x=1/3). The behavior of Cu+ ions in highly doped regions suggests the occurrence of a two-dimensional liquid-solid state transition based on the temperature dependence of the x-ray diffuse scattering.
- Physical Review B
Physical Review B 99(8), 081111(R), 2019-02
American Physical Society