Fermi-Surface Instability in the Heavy-Fermion Superconductor UTe_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• UT e$_{2}$ is a recently discovered heavy-fermion superconductor.
• Understanding its electronic properties is key to comprehending unconventional superconductivity.

Purpose of the Study:

• Investigate the electronic properties of UTe$_{2}$ under high magnetic fields.
• Characterize the superconducting and normal states of UTe$_{2}$.

Main Methods:

• Transport measurements, including thermoelectric power, were conducted up to 29 T.
• Magnetic field was applied along the easy magnetization axis (a-axis) of the body-centered orthorhombic structure.

Main Results:

• Thermoelectric power showed a linear temperature dependence above the superconducting transition (T$_{SC}$=1.5 K), indicating a Fermi liquid regime.
• Successive anomalies in thermoelectric power at critical magnetic polarization values were observed, identifying a Lifshitz transition.
• The Lifshitz transition occurred at a critical magnetization of 0.4 $\mu$$_{B}$, consistent with transitions along other axes.

Conclusions:

• Superconductivity in UTe$_{2}$ develops within a Fermi liquid regime.
• Strong electronic correlations play a significant role in the metallic ground state of UTe$_{2}$.
• The observed Lifshitz transition provides insights into the complex electronic structure of this heavy-fermion superconductor.