Interface-enhanced ferromagnetism with long-distance effect in van der Waals semiconductor

TL;DR

This study demonstrates that interfacial engineering with tungsten can significantly enhance the Curie temperature and magnetic properties of 2D ferromagnetic semiconductor Cr2Ge2Te6, enabling more practical 2D spintronic devices.

Contribution

The paper reveals a novel long-distance interfacial effect that boosts ferromagnetism in 2D semiconductors, surpassing previous limitations of low Curie temperatures.

Findings

Curie temperature increased by 130% with tungsten adjacency

Interfacial W-Te bonding enhances magnetic anisotropy

Long-distance effect persists over more than 10 nanometers

Abstract

Ferromagnetic semiconductors discovered in two-dimensional (2D) materials open an avenue for highly integrated and multifunctional spintronics. The Curie temperature (TC) of existed 2D ferromagnetic semiconductors is extremely low and the modulation effect of their magnetism is limited compared with their 2D metallic counterparts. The interfacial effect was found to effectively manipulate the three-dimensional magnetism, providing a unique opportunity for tailoring the 2D magnetism. Here we demonstrate that the TC of 2D ferromagnetic semiconductor Cr2Ge2Te6 can be enhanced by 130% (from ~65 K to above 150 K) when adjacent to a tungsten layer. The interfacial W-Te bonding contributes to the TC enhancement with a strong perpendicular magnetic anisotropy (PMA), guaranteeing an efficient magnetization switching by the spin-orbit torque with a low current density at 150 K. Distinct from the rapid attenuation in conventional magnets, the interfacial effect exhibits a weak dependence on Cr2Ge2Te6 thickness and a long-distance effect (more than 10 nanometers) due to the weak interlayer coupling inherent to 2D magnets. Our work not only reveals a unique interfacial behavior in 2D materials, but also advances the process towards practical 2D spintronics.