265 / 2023-04-23 19:12:03

Pressure induced electronic and structural transition in HfS2

Transition metal dichalcogenides,high pressure,phase transition

高压物理与材料科学 > 功能材料-海报

Transition metal dichalcogenides (TMDCs) have a typical two-dimensional (2D) structure. As an effective method to adjust the properties of TMDCs, high pressure has induced many interesting properties such as metallization or even superconductive. The emergences of these electronic phenomena are usually related to the three-dimensional (3D) phase transition because of the more compact structure. However, we found that 1T-HfS₂ can maintain its semiconducting nature with a narrow band gap after 3D transition. The 2D-3D (P-3m1 to Immm) structural transition is showed by XRD at ~12 GPa, but Raman spectra and optical measurement indicate that a structural/electronic transition occurs as early as 9.2 GPa. The new semiconducting state has a narrow band gap and could be stable over a wide pressure range up to ~65 GPa. The metallization finally occurs at 68.6 GPa, the maximum pressure of in this work. This robust semiconducting state and special electronic behavior is unique at TMDCs families, which implies an unusual electronic structure of the 3D Immm structure. This work will extend our understanding on the structure and electronic properties in the TMDC family and benefit the exploration of novel electronic state and functional devices.