Pressure-induced metallic state in a van der Waals cluster Mott insulator Nb3Cl8

We report on the pressure-induced metallization of a van der Waals cluster Mott insulator Nb3Cl8 by employing the resistivity measurements under high pressure. Upon compression, its resistance and energy gap are sup-pressed gradually with exhibiting the fully metallic state at a critical pressure of Pc approximate to 70 GPa. Hall resistance measurements revealed a significant band-structure reconstruction around Pc, where the dominant charge carriers are altered from hole-to electron-type and the carrier concentration experiences a sharp increase in the metallic state. In addition, high-pressure synchrotron XRD measurements uncover a possible structural phase transition around Pc. Our further first-principles calculations reproduced the pressure-driven structure transition and the corresponding metallic state above Pc. The present study demonstrates a feasible high-pressure route to realize the metallization of cluster Mott insulator Nb3Cl8.

Automated summary

We successfully achieved the pressure-induced metallization of van der Waals cluster Mott insulator Nb3Cl8 through high-pressure measurements and calculations, and revealed the band-structure reconstruction and structural phase transition.