Korshunov Maxim M, Kuzmichev Svetoslav A, Kuzmicheva Tatiana E
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok, 660036 Krasnoyarsk, Russia.
Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
Materials (Basel). 2022 Sep 3;15(17):6120. doi: 10.3390/ma15176120.
Quasiparticle excitations provide viable information on the physics of unconventional superconductors. Higgs and Leggett modes are some of the classic examples. Another important bosonic excitation is the spin exciton originating from the sign-changing superconducting gap structure. Here we report a direct observation of the temperature-dependent spin exciton in the Andreev spectra of iron-based superconductors. Combined with the other experimental evidence, our observation confirms the extended -wave (s±) order parameter symmetry and indirectly proves the spin-fluctuation mechanism of Cooper pairing.
准粒子激发为非常规超导体的物理性质提供了切实可行的信息。希格斯模和莱格特模就是一些典型例子。另一种重要的玻色子激发是源自超导能隙结构符号变化的自旋激子。在此，我们报告在铁基超导体的安德烈夫光谱中对温度依赖的自旋激子的直接观测。结合其他实验证据，我们的观测证实了扩展波（s±）序参量对称性，并间接证明了库珀对的自旋涨落机制。
