The paper reports complementary studies of the order parameter of the newly discovered iron-based superconductor, KCa₂Fe₄As₄F₂ (T_c = 34 K), that consists of alternating blocks of KFe₂As₂ (122) phase and CaFeAsF (1111) phase. We performed high-resolution intrinsic multiple Andreev reflection spectroscopy supplemented with self-field critical current measurements. Andreev spectra, obtained by means of a break-junction technique reveal two distinct superconducting order parameters – Δ_L and Δ_S.T heir temperature dependencies were measured from 1.5 K to T_c. The shape of Andreev reflections dips, corresponding to the two gaps, are symmetrical, which is a signature of s-wave order parameter. Temperature dependence of the self-field critical current can also be described by two s-wave gaps model.

_{该论文报告了对新发现的铁基超导体 KCa 2} Fe ₄ As ₄ F ₂ ( T _c = 34 K)的序参数的补充研究，该超导体由 KFe ₂ As ₂ (122) 相和 CaFeAsF的交替块组成【1111】相。我们进行了高分辨率本征多重安德烈夫反射光谱并辅以自场临界电流测量。通过断结技术获得的安德烈夫谱揭示了两个不同的超导有序参数 - Δ _L和 Δ _S。测量了从 1.5 K 到T _c的温度依赖性。对应于两个间隙的Andreev反射波谷的形状是对称的，这是s波阶次参数的特征。自场临界电流的温度依赖性也可以通过两个横波间隙模型来描述。