Sn$_{0.06}$Cr$_3$Te$_4$: A Skyrmion Superconductor

TL;DR

This paper reports the discovery of superconductivity in a ferromagnetic skyrmion system Cr$_3$Te$_4$ induced by Sn intercalation, revealing coexistence of superconductivity, magnetism, and topological effects, and suggesting new topological quantum materials.

Contribution

First demonstration of superconductivity in a skyrmion lattice system, with insights into separate conduction channels and topological Hall effect tuning due to Sn intercalation.

Findings

Superconductivity observed below 3.5 K in Sn$_{0.06}$Cr$_3$Te$_4$

Bulk superconductivity confirmed by specific heat jump and volume fraction

Coexistence of superconductivity, magnetism, and topological Hall effect

Abstract

Topological superconductors are an exciting class of quantum materials from the point of view of the fundamental sciences and potential technological applications. Here, we report on the successful introduction of superconductivity in a ferromagnetic layered skyrmion system Cr$_3$Te$_4$, obtained by the Sn intercalation, below a transition temperature of $T_c$$\approx$3.5 K. We observe several interesting physical properties, such as superconductivity, magnetism, and the topological Hall effect, simultaneously in this system. Despite the magnetism and Meissner effects being anisotropic, the superconductivity observed from the in-plane electrical resistivity ($\rho_{\it{bc}}$) is nearly isotropic between $H\parallel \it{bc}$ and $H\parallel \it{a}$, suggesting separate channels of conduction electrons responsible for the superconductivity and magnetism of this system, which is also supported by our spin-resolved DFT calculations. We identify two orders of higher carrier density in superconducting Sn$_{0.06}$Cr$_{3}$Te$_4$ than the parent Cr$_3$Te$_4$. A jump in the specific heat is noticed around the $T_c$ with a volume fraction of 33\%, confirming the bulk superconductivity in Sn$_{0.06}$Cr$_{3}$Te$_4$. In addition to the introduction of superconductivity, tuning of topological Hall properties is noticed with Sn intercalation. Our observation of superconductivity in a skyrmion lattice brings up a new class of topological quantum materials.