A key question regarding the unconventional superconductivity of Sr2RuO4 remains whether the order parameter is single- or two-component. Under a hypothesis of two-component superconductivity, uniaxial pressure is expected to lift their degeneracy, resulting in a split transition. The most direct and fundamental probe of a split transition is heat capacity. Here, we report measurement of heat capacity of samples subject to large and highly homogeneous uniaxial pressure. We place an upper limit on the heat-capacity signature of any second transition of a few percent of that of the primary superconducting transition. The normalized jump in heat capacity, ΔC/C, grows smoothly as a function of uniaxial pressure, favoring order parameters which are allowed to maximize in the same part of the Brillouin zone as the well-studied van Hove singularity. Thanks to the high precision of our measurements, these findings place stringent constraints on theories of the superconductivity of Sr2RuO4.

关于非常规超导性的一个关键问题 秒r2电阻你哦4保持顺序参数是单分量还是双分量。在双组分超导假设下，单轴压力有望解除它们的简并性，导致分裂转变。分裂转变最直接和最基本的探测是热容。在这里，我们报告了在大且高度均匀的单轴压力下样品的热容量的测量。我们将任何第二次转变的热容量特征设置为一次超导转变的几个百分点的上限。热容的标准化跳跃，ΔC/C，作为单轴压力的函数平稳增长，有利于允许在布里渊区的同一部分与充分研究的范霍夫奇点最大化的阶参数。由于我们测量的高精度，这些发现对超导理论施加了严格的限制。秒r2电阻你哦4.