Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2012 Jan 13;108(2):027001. doi: 10.1103/PhysRevLett.108.027001. Epub 2012 Jan 11.
We use heat-capacity measurements as a function of field rotation to identify the nodal gap structure of CeIrIn(5) at pressures to 2.05 GPa, deep inside its superconducting dome. A fourfold oscillation in the heat capacity at 0.3 K is observed for all pressures, but with its sign reversed between 1.50 and 0.90 GPa. On the basis of recent theoretical models for the field-angle-dependent specific heat, all data, including the sign reversal, imply a d(x(2)-y(2)) order parameter with nodes along [110], which constrains theoretical models of the pairing mechanism in CeIrIn(5).
我们利用热容量随磁场旋转的函数关系，在压力达到 2.05GPa 时对 CeIrIn(5)的节隙结构进行了研究，该压力远在其超导能区以内。在所有压力下，我们都观察到在 0.3K 时热容量呈现四重振荡，但在 1.50 到 0.90GPa 之间其符号发生了反转。基于最近提出的磁场角度相关比热理论模型，所有数据（包括符号反转）都表明存在一个沿[110]方向的节点的 d(x(2)-y(2))序参量，这对 CeIrIn(5)中的配对机制理论模型形成了限制。
