Experts at the University of Chicago have progressed in advancing an optical storage using MnBi2Te4, a magnetic topological insulator with rapidly responsive properties to light.
Academics at the University of Chicago Pritzker School of Molecular Engineering (PME) have seen unforeseen strides towards formulating a fresh optical storage that can efficiently and quickly stockpile and retrieve computational data. In the course of examining a complex material comprising of manganese, bismuth, and tellurium (MnBi2Te4), the researchers noted that the material’s magnetic features altered promptly and effortlessly when exposed to light. This implies that information can be embedded within the magnetic states of MnBi2Te4 using a laser.
“This firmly emphasizes how primary science can foster innovative thoughts regarding engineering applications in a very direct manner,” mentioned Shuolong Yang, associate professor of molecular engineering and principal author of the new study. “Our primary objective was to fathom the molecular particulars of this material which ultimately led us to identify its unexplored attributes that make it exceptionally practical.”
Published on August 9 in the publication Science Advances, Yang and collaborators illustrated how the electrons in MnBi2Te4 rival between two opposing states – a topological state beneficial for quantum information encoding and a light-responsive state advantageous for optical retention.
Tackling a Topological Conundrum
Previously, MnBi2Te4 was explored for its potential as a magnetic topological insulator (MTI), a material that acts like an insulator internally but carries current on its external surfaces. In an ideal MTI under 2D constraints, a quantum phenomenon arises where an electric current flows in a 2-dimensional stream along its margins. These so-called “electron highways” have the capacity to encode and transport quantum facts.
Although researchers anticipated that MnBi2Te4 should be capable of sustaining such an electron pathway, practically working with the material has been challenging.
“Our primary aim was to comprehend why attaining these topological characteristics in MnBi2Te4 was so problematic,” mentioned Yang. “Why is the anticipated physics absent?”
To unravel this enigma, Yang’s team embraced progressive spectroscopy methods permitting them to visualize the conduct of electrons within MnBi2Te4 concurrently on ultrafast intervals. They applied time- and angle-resolved photoemission spectroscopy crafted in the Yang laboratory and collaborated with Xiao-Xiao Zhang’s team at the University of Florida to execute time-resolved magneto-optical Kerr effect (MOKE) assessments, allowing magnetism observation.
“This amalgamation of approaches furnished us with direct insights into not only the electron movements but also their connection to light,” Yang elaborated.
Refining Materials for Emerging Technologies
Upon assessing the spectroscopy outcomes, it became evident why MnBi2Te4 was not adhering as a sound topological material. There existed a quasi-2D electronic condition contending with the topological phase for electrons.
“A wholly distinct form of surface electrons replaced the original topological surface electrons,” revealed Yang. “Yet, this quasi-2D state actually holds a unique and beneficial trait.”
The alternate electron state possessed a close linkage between magnetism and external light photons — not valuable for delicate quantum information but exactly meeting the criteria for an effective optical retention.
To delve further into this prospective application of MnBi2Te4, Yang’s squad is preparing experiments leveraging a laser to modify the material’s attributes. They believe an optical storage utilizing MnBi2Te4 could surpass contemporary electronic memory devices by significant multiples in terms of efficiency.
Yang also emphasized that an enhanced comprehension of the equilibrium between the two electron states on the exterior of MnBi2Te4 could heighten its suitability as an MTI and its relevance in quantum information storage.
“Possibly, we could grasp adjusting the equilibrium between the initial, theoretically foreseen state and this novel quasi-2D electronic state,” he remarked. “This could be viable by manipulating our synthesis conditions.”
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