Transport properties and anisotropy of Rb0.8Fe2Se2 single crystals

TL;DR

This study synthesizes Rb0.8Fe2Se2 single crystals, characterizes their superconducting and anisotropic properties, and compares their anisotropy to related compounds, revealing stronger two-dimensional electronic behavior.

Contribution

It provides detailed measurements of the superconducting transition, resistivity anomaly, and anisotropy in Rb0.8Fe2Se2, highlighting its higher anisotropy compared to similar iron-based superconductors.

Findings

Superconducting transition temperatures of 31 K (onset) and 28 K (zero)

Anisotropy of upper critical field around 3.5, decreasing with temperature

Stronger two-dimensional Fermi surface characteristics inferred

Abstract

Single crystals of Rb{0.8}Fe2Se2 are successfully synthesized with the superconducting transition temperatures T_c{onset}= 31 K and T_c{zero}= 28 K. A clear anomaly of resistivity was observed in the normal state at about 150 K, as found in a similar system KxFe2Se2. The upper critical field has been determined with the magnetic field along ab-plane and c-axis, yielding an anisotropy of about 3.5. The angle dependent resistivity measured below T_c allow a perfect scaling feature based on the anisotropic Ginzburg-Landau theory, leading to a consistent value of the anisotropy which decreases from about 3.6 at around T_c to 2.9 at 27 K. Comparing to the anisotropy determined for Ba0.6K0.4Fe2As2 and Ba(Fe0.92Co0.08)2As2 using the same method, we find that the present sample is more anisotropic and the Fermi surfaces with stronger two dimensional characters are expected.