Charge-density wave transition of $1T{-\mathrm{V}\mathrm{S}\mathrm{e}}_2$ studied by angle-resolved photoemission spectroscopy

High-resolution angle-resolved photoemission spectroscopy (ARPES) has been performed on a layered transition-metal dichalcogenide (TMDC) $1T-{\mathrm{VSe}}_2$ to study the $(4\mathrm{}\times 4)$ charge-density wave (CDW) mechanism. We observed a partial Fermi-surface (FS) nesting on the electronlike FS centered at the M (L) point. The spectral weight near $E_F$ is considerably suppressed below the transition temperature ${(T}_c=110\mathrm{}\mathrm{K})$ around the nested portion, while a negligible spectral change is observed even across $T_c$ in other portions of FS. This suggests that the CDW transition in $1T-{\mathrm{VSe}}_2$ is caused by the three-dimensional FS nesting. Implications are discussed in relation to the physical properties of $1T-{\mathrm{VSe}}_2$ as well as the ARPES results of other TMDC’s.