X-ray-diffraction study of the periodic lattice distortion associated with a charge-density wave in1T-VSe2

Abstract

The periodic lattice distortion associated with a charge-density wave in $1T$-V${\mathrm{Se}}_2$ was investigated by x-ray diffraction. The charge-density-wave transition was observed at 110 K. From the observation of the satellite reflections the wave vector of the periodic lattice distortion was determined to be $(0.250\mathrm{}\pm 0.003)a^{*}+(0.307\mathrm{}\pm 0.003)c^{*}$ below 85 K and $(0.250\mathrm{}\pm 0.003)a^{*}+(0.314\mathrm{}\pm 0.003)c^{*}$ above 85 K. The $a^{*}$ component is temperature independent, while the $c^{*}$ component shows an abrupt change in the vicinity of 85 K. Discussion is developed on the physical origin of the incommensurability of the $c^{*}$ component.