Pressure-Induced Electronic and Structural Transition in Nodal-Line Semimetal ZrSiSe.

The nodal-line semimetals have recently gained attention as a promising material due to their exotic electronic structure and properties. Here, we investigated the structural evolution and physical properties of nodal-line semimetal ZrSiSe under pressure via experiments and theoretical calculations. An isostructural electronic transition is observed at ∼6 GPa. Upon further compression, the original tetragonal phase starts to transform into an orthorhombic phase at ∼13 GPa and the two phases coexist until the maximal experimental pressure. By analysis of the electronic band structure, we suggest that the significant changes in the Fermi surface contribute to the occurrence of the isostructural electronic transition. The results provide a new insight into the structure and properties of ZrSiSe.