S. A. Kuzmichev, I. V. Morozov, A. I. Shilov, Ye. O. Rakhmanov, T. E. Kuzmicheva, “Doping evolution of the superconducting order parameter of Na(Fe, Co)As alkali-metal pnictides”, Pis'ma v Zh. Èksper. Teoret. Fiz., 2024, Volume 120, Issue 2,Pages <nobr>130

CONDENSED MATTER

Doping evolution of the superconducting order parameter of Na(Fe, Co)As alkali-metal pnictides

S. A. Kuzmichev^ab, I. V. Morozov^c, A. I. Shilov^b, Ye. O. Rakhmanov^ca, T. E. Kuzmicheva^a

^a Faculty of Physics, Moscow State University, Moscow, 119991 Russia
^b Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia
^c Faculty of Chemistry, Moscow State University, Moscow, 119991 Russia

Abstract: Using incoherent multiple Andreev reflection effect spectroscopy, we have studied the multiple-gap superconducting state of underdoped and overdoped Na(Fe, Co)As single crystals. We directly determined the magnitudes of the microscopic superconducting order parameters, their temperature dependences, and characteristic ratios $2\Delta(0)/k_BT_c$. The obtained large data statistics unambiguously proves a significant decrease in the degree of the large superconducting gap possible anisotropy in the overdoped compositions away from the antiferromagnetic and nematic regions of the doping phase diagram.

Received: 06.06.2024
Revised: 13.06.2024
Accepted: 13.06.2024

DOI: 10.31857/S1234567824140088