Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan.
Phys Rev Lett. 2015 Mar 13;114(10):105304. doi: 10.1103/PhysRevLett.114.105304. Epub 2015 Mar 10.
The transverse acoustic impedance of superfluid ^{3}He was measured in the A1 and A2 phases up to 13 T to investigate the surface states in nonunitary superfluids. The temperature dependence of the impedance was much larger in the A1 phase than in the A2 phase. This nonsymmetric behavior indicates that momentum exchange with walls for spin-down surface states is quite different from that for spin-up surface states. The spin-dependent response might be a reflection of an essential feature of the nonunitary states where gap amplitudes depend on spin states. Weak-coupling theories ignore any spin-dependent processes and do not account for the nonsymmetric behavior.
超导 ^{3}He 的横向声阻抗在 A1 和 A2 相被测量到 13 T，以研究非幺正超流中的表面态。在 A1 相中，阻抗的温度依赖性比 A2 相大得多。这种不对称行为表明，对于自旋向下的表面态，与壁的动量交换与对于自旋向上的表面态是完全不同的。自旋相关的响应可能反映了非幺正态的一个基本特征，其中间隙幅度取决于自旋态。弱耦合理论忽略了任何自旋相关的过程，也无法解释这种不对称的行为。
