Designation of Intra-layer and Intercalated High Entropy Quasi-2D Compounds

TL;DR

This paper introduces novel high-entropy quasi-2D compounds based on transition metal dichalcogenides, demonstrating superconductivity and complex magnetic states, and exploring their structural tunability and potential for discovering new physics.

Contribution

It presents two innovative schemes for creating high-entropy structures in TMDCs, including intra-layer and intercalated methods, revealing new magnetic and superconducting properties.

Findings

Superconductivity with Tc~7.4 K in Mo-rich HEMX2.

Observation of ferromagnetic spin-glass states in intercalated compounds.

Structural tunability with different lattice arrangements and magnetic states.

Abstract

Here, we designed two promising schemes to realize the high-entropy structure in a series of quasi-two-dimensional compounds, transition metal dichalcogenides (TMDCs). In the intra-layer high-entropy plan, (HEM)X2 compounds with high-entropy structure in the MX2 slabs were obtained, here HEM means high-entropy metals, such as TiZrNbMoTa. And superconductivity with a Tc~7.4 K was found in a Mo-rich HEMX2. On the other hand, in the intercalation plan, we intercalated HEM-atoms (FeCoCrNiMn) into the gap between the sandwiched-MX2 slabs resulting in a series of (HEM)xMX2 compounds, x in the range of 0~0.5, in which HEM is mainly composed of 3d transition metal elements, such as FeCoCrNiMn. As the introduction of multi-component magnetic atoms, ferromagnetic spin-glass states with strong 2D characteristics ensued. Tuning the x content, three kinds of two in the high-entropy intercalated layer were observed including the 1*1 triangular lattice and two kinds of superlattices \sqrt3*\sqrt3 and \sqrt3*2 in x=0.333 and x>0.5, respectively. Meanwhile, the spin frustration in the two-dimensional high-entropy magnetic plane will be enhanced with the development of \sqrt3*\sqrt3 and will be reduced significantly when changing into the \sqrt3*2 phase. The high-entropy TMDCs and versatile two-dimensional high-entropy structures found by us possess great potentials to find new physics in low-dimensional high-entropy structures and future applications.