Nano CrGeTe3: Topological Hall Effect in the Metallic State under High Pressure

TL;DR

This paper explores how high pressure changes the magnetic and electrical properties of CrGeTe3 nanosheets, revealing new topological effects useful for spintronics.

Contribution

The study demonstrates pressure-induced phase transitions and topological Hall effects in CrGeTe3 nanosheets.

Findings

CrGeTe3 transitions from an insulator to a metal at 6.02 GPa pressure.

At 25.33 GPa, CrGeTe3 changes from ferromagnetic to Néel antiferromagnetic state.

High-pressure topological Hall effect is linked to Néel-type skyrmions.

Abstract

The ferromagnetic (FM) properties of the van der Waals charge transfer insulator CrGeTe3 provide a promising avenue for concurrently controlling magnetic and electrical characteristics. This enables the potential integration of devices using nanoscale materials. In this research, we have effectively produced highly stable CrGeTe3 nanosheets by utilizing a Cr2Te3 template. Additionally, we show that the magnetic and electrical characteristics of CrGeTe3 single crystals can be continuously adjusted through the application of pressure. Electrical transport measurements reveal that CrGeTe3 transitions from an insulator under ambient conditions to a metallic state at 6.02 GPa. After reaching 25.33 GPa, CrGeTe3 undergoes a phase transition from the FM state to the Néel antiferromagnetic state at 30 K. This transition highlights the important impact of pressure on exchange interactions, corroborating density functional theory calculations. Micromagnetic simulation shows that the high-pressure topological Hall effect above 25.33 GPa originates from the Néel-type skyrmion. The interaction observed between magnetic couplings and high pressure provides crucial insights into the novel topological transport phenomena and their underlying physics, which is valuable for advancing spintronics devices and other emerging electronic technologies.

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