Enhanced superconductivity and anisotropy of FeTe0.6Se0.4 single crystals with Li-NH3 intercalation

TL;DR

This study demonstrates that Li-NH3 intercalation in FeTe0.6Se0.4 crystals enhances superconductivity, increases anisotropy, and induces multiband electronic behavior, revealing new insights into intercalation effects on iron-based superconductors.

Contribution

It provides a systematic analysis of how Li-NH3 intercalation modifies superconducting and electronic properties in FeTe0.6Se0.4, highlighting increased Tc and anisotropy.

Findings

Superconducting transition temperature is increased by intercalation.

Electronic anisotropy is significantly enhanced in intercalated crystals.

Hall coefficient indicates a shift to electron-dominated conduction at low temperatures.

Abstract

We report a systematic study of anisotropy resistivity, magnetoresistance and Hall effect of Li0.32(NH3)yFe2Te1.2Se0.8 single crystals. When compared to the parent compound FeTe0.6Se0.4, the Li-NH3 intercalation not only increases the superconducting transition temperature, but also enhances the electronic anisotropy in both normal and superconducting states. Moreover, in contrast to the parent compound, the Hall coefficient RH becomes negative at low temperature, indicating electron-type carriers are dominant due to Li doping. On the other hand, the sign reverse of RH at high temperature and the failure of scaling behavior of magnetoresistance imply that hole pockets may be still crossing or just below the Fermi energy level, leading to the multiband behavior in Li0.32(NH3)yFe2Te1.2Se0.8.