Pressure induced phase transition in heavy fermion metal UTe2: A first-principles study

Abstract

Heavy fermion metals are a strongly correlated electronic system with large effective mass of quasi-electrons. It also exhibits abundant physical properties at ambient pressure. Using crystal structure predictions and first-principles calculations, we found that an eight-fold coordinated ambient-pressure Immm phase of UTe2 transforms into a ten-fold coordinated high-pressure I4/mmm phase at 9 GPa. Considering the strong correlation effect of f electrons, the PBE + U method was used in our calculation. The ELF calculation results show that the pressure will facilitate the lone pair electrons of Te in ambient-pressure phase of UTe2 to participate in chemical bonding in order to achieve the high-pressure I4/mmm phase. Additionally, we found that the bulk modulus of the I4/mmm phase can reach 137 GPa. The work provides a possible route for studying phase transitions of UTe2 under pressure.