Andreev spectroscopy of iron-based superconductors of the 1111, 111, and 122 families

by Dr Tatiana Kuzmicheva (Lebedev Physical Institute (LPI), Russian Academy of Science (RAS), Moscow, Russia)

Wednesday 29 Mar 2023, 15:00 → 16:00 Asia/Shanghai

ONLINEDr Tatiana Kuzmicheva, Lebedev Physical Institute (LPI), Russian Academy of Science (RAS), Moscow, Russia

Abstract

The experimental data obtained using incoherent multiple Andreev reflection effect (IMARE) spectroscopy of SnS junctions in several families of iron-based superconductors are reported. To form superconductor - thin normal metal-superconductor (SnS) junctions, we use a unique planar mechanically controlled break-junction technique (MCPBJ). Generally, below Tc IMARE causes a series of features in the I(V) and dI(V)/dV characteristic of an SnS junction that directly determines the magnitude of the superconducting gap and its temperature dependence. The high energy resolution of the IMARE spectroscopy of MCPBJs gives a possibility to estimate the gap anisotropy in the k-space.

 

We have studied the following Fe-based superconductors in a wide range of doping and Tc:

- the 1111 family oxypnictides Gd(O,F)FeAs, (Sm,Th)OFeAs, Ce(O,F)FeAs, La(O,F)FeAs,

- the 122 family pnictides Ba(Fe,Ni)2As2,

- the 111 family LiFeAs and NaFeAs.

In these materials, we observe a multiple-gap superconductivity, directly determine the values, characteristic ratios and temperature dependences of the superconducting gaps, and discuss their possible anisotropy in the k-space detected in the 122 and 111 families. Summarizing the experimental data, we study the evolution of the superconducting properties within the doping phase diagram.

Biography

Since 2010 Dr Tatiana Kuzmicheva has been working at Lebedev Physical Institute (LPI), currently as a senior researcher. In 2010 she graduated from the Faculty of Physics at Lomonosov Moscow State University (MSU). In 2015 Tatiana got a PhD degree at Lebedev Physical Institute. Tatiana is a member of the Scientific Council of Lebedev Physical Institute RAS and the Scientific Council of the V.L. Ginzburg Center for High-Temperature Superconductivity and Quantum Materials, P.N. Lebedev Physical Institute. She received several awards: The prize for young scientists, Moscow State University, Faculty of physics in 2009, the S.I. Vavilov award for young scientists, Lebedev Physical Institute in 2011, and the award from The Council of the President of the Russian Federation for young scientists in 2016. She is an author of 41 publications and more than 100 talks at Russian and international conferences (including 8 invited talks).

Division

Condensed Matter

Other information

Vedio link: https://vshare.sjtu.edu.cn/open/73f85a67c9be74ed1b2cbf031d2e4922