High-sensitivity heat-capacity measurements on Sr ₂ RuO ₄ under uniaxial pressure

Significance Research on the unconventional superconductivity of S mathvariant="normal">r 2 mathvariant="normal">R mathvariant="normal">u mathvariant="normal">O 4 is undergoing a renaissance since recent spin susceptibility measurements ruling out triplet order parameter which had been widely favored for over two decades. With ultrasound, Kerr rotation, and muon relaxation data all providing evidence two-component parameter, it vital that this possibility be investigated thermodynamically by studying dependence heat-capacity anomaly uniaxial pressure. Here, relevant experimental results are combined with theoretical analysis shows how strongly constrain theories parameter. In particular, we do not observe any signs transition splitting two-order-parameter components. thus offers unique test bed superconductivity.