Sr3Ru2O7: Thermodynamics of Phase Formation in a Quantum Critical Metal

Understand

The behaviour of matter near zero temperature continuous phase transitions, or 'quantum critical points' (QCPs) is a central topic of study in condensed matter physics.

• In fermionic systems, fundamental questions remain unanswered: the nature of the quantum critical regime is unclear because of the apparent breakdown of the concept of the quasiparticle, a cornerstone of existing theories of strongly interacting metals.
• Even less is known experimentally about the formation of ordered phases from such a quantum critical 'soup'.
• Here, we report a study of the specific heat across the phase diagram of the model system Sr3Ru2O7, which features an anomalous phase whose transport properties are consistent with those of an electronic nematic.