Unconventional insulator-to-metal phase transition in Mn3Si2Te6

Published December 12, 2024

(a) Reflectance ratios of Mn3Si2Te6 as a function of magnetic field at 5.5 K. (b) Crystal structure showing two distinct Mn sites.

The physical properties of any solid material are determined by what happens in the quantum realm. How the electrons interact with each other, their surrounding lattice, any applied electric or magnetic fields, etc… will dictate properties such as hardness, ductility, strength or resistivity. The electrical properties of Mn₃Si₂Te₆ can be altered by the application of strong magnetic fields causing the material to transition from an insulator to a metal. To understand the process behind this transformation, MagLab users employed infrared spectroscopy and high fields to illuminate the physical processes behind this behavior.

What did scientists discover?

Scientists used high-field infrared spectroscopy to study how a Manganese, Silicon, Tellurium compound (Mn₃Si₂Te₆) changes from an insulator to a metal under a magnetic field. Instead of becoming a regular metal, it forms a weak metallic state with trapped charges, revealing unique magnetic and electronic behavior.

Why is this important?

This research reveals how materials switch from insulators to metals at a microscopic level, uncovering new quantum states and paving the way for designing materials with exceptional magnetoresistance. These materials have potential uses in technologies like data storage and sensors.

Who did the research?

Yanhong Gu¹, Kevin A. Smith¹, Amartyajyoti Saha², Chandan De³, Choong-jae Won³, Yang Zhang¹, Ling-Fang Lin¹, Sang-Wook Cheong^3,4, Kristjan Haule⁴, Mykhaylo Ozerov⁵, Turan Birol², Christopher Homes⁶, Elbio Dagotto¹, Janice L. Musfeldt¹

¹University of Tennessee; ²University of Minnesota; ³Pohang University of Science and Technology; ⁴Rutgers University; ⁵National MagLab; ⁶Brookhaven National Laboratory

Why did they need the MagLab?

Magnetoresistance happens when a material’s resistance changes due to a magnetic field, but understanding why it happens takes a deeper look and specialized instruments and techniques. Using specialized high-field infrared measurements available at the MagLab, scientists were able to probe the behavior of both the crystal structure and charge carriers simultaneously. This was made possible by advanced optical tools developed specifically for this research.