Evolution of Fermi-liquid interactions in Sr2RuO4 under pressure

Area of Science:

• Condensed matter physics
• Materials science
• Superconductivity research

Background:

• Strontium ruthenate (Sr2RuO4) is an unconventional superconductor.
• Understanding the pressure dependence of its electronic properties is crucial for elucidating its superconducting mechanism.

Purpose of the Study:

• To investigate the effects of hydrostatic pressure on the resistivity and Fermi surface of Sr2RuO4.
• To examine the relationship between pressure, dimensionality, and superconductivity in Sr2RuO4.
• To test the hypothesis of a ferromagnetic quantum critical point near 3 GPa.

Main Methods:

• Resistivity measurements under varying temperature, magnetic field, and hydrostatic pressure (up to 3.3 GPa).
• Shubnikov-de Haas (SdH) effect measurements to probe Fermi surface properties.
• Analysis of many-body enhancements and superconducting transition temperature (Tc).

Main Results:

• Increasing pressure enhances the two-dimensionality of the Fermi surface sheet responsible for superconductivity.
• Both many-body enhancements and the superconducting transition temperature (Tc) decrease gradually with increasing pressure.
• The results contradict previous theories suggesting a ferromagnetic quantum critical point around 3 GPa.

Conclusions:

• The pressure-induced changes in Sr2RuO4 are consistent with models of orbital-dependent superconductivity.
• The absence of a ferromagnetic quantum critical point at 3 GPa suggests alternative mechanisms govern its electronic behavior.
• This study provides critical insights into the complex interplay of pressure, dimensionality, and superconductivity in unconventional materials.