Revolutionising Electronics: Scientists Manipulate ‘Electron Universe’ Geometry in Magnets

Researchers at Tohoku University and the Japan Atomic Energy Agency have developed a way to manipulate the ‘electron universe’ within a magnetic material. This breakthrough could lead to the design of innovative spintronic devices. The team successfully manipulated the quantum-metric structure at room temperature in a thin-film heterostructure. The lead author of the study, Jiahao Han, explained that they can manipulate the quantum metric by modifying the magnetic structure of the material. Theoretical analyst Yasufumi Araki and principal investigator Shunsuke Fukami also contributed to the research. The findings were published in Nature Physics.

Quantum Metric: A New Frontier in Spintronics

Researchers from Tohoku University and the Japan Atomic Energy Agency have made significant strides in manipulating the quantum metric, a geometric property of electronic quantum states, within a magnetic material under ambient conditions. This development, published in Nature Physics, could potentially revolutionize the field of spintronics, a technology that utilizes the quantum spin and charge of electrons to store and process information.

Beyond Ohm’s Law: The Quantum Metric and Non-Ohmic Conduction

Electric conduction, a fundamental principle in many devices, is governed by Ohm’s law, which states that current responds proportionally to applied voltage. However, to develop new devices, scientists need to go beyond this law. This is where the quantum metric comes into play. The quantum metric, a property inherent to the material itself, can generate non-Ohmic conduction, a type of electrical conduction that does not follow Ohm’s law.

The term ‘quantum metric’ is inspired by the ‘metric’ concept in general relativity, which describes how the geometry of the universe distorts under the influence of intense gravitational forces. In a similar vein, the quantum metric delineates the geometry of the ‘electron universe,’ and understanding and harnessing this metric is crucial for designing non-Ohmic conduction within materials.

Manipulating the Quantum Metric: A Breakthrough in Spintronics

The research team successfully manipulated the quantum-metric structure at room temperature in a thin-film heterostructure composed of an exotic magnet, Mn3Sn, and a heavy metal, Pt. Mn3Sn exhibits a unique magnetic texture when adjacent to Pt, which is significantly modulated by an applied magnetic field. The team detected and magnetically controlled a non-Ohmic conduction termed the second-order Hall effect, where voltage responds orthogonally and quadratically to the applied electric current. Theoretical modeling confirmed that these observations can be exclusively described by the quantum metric.

The Quantum Metric: A Fundamental Concept in Material Science

The quantum metric is a fundamental concept that connects the material properties measured in experiments to the geometric structures studied in mathematical physics. However, confirming its evidence in experiments has remained challenging. The team’s experimental approach to accessing the quantum metric could potentially advance theoretical studies in this field.

Quantum Metric: A Game Changer in Device Design

Until now, the quantum metric was believed to be inherent and uncontrollable, much like the universe. However, this perception needs to change. The team’s findings, particularly the flexible control at room temperature, may offer new opportunities to develop functional devices such as rectifiers and detectors in the future. This breakthrough could pave the way for the design of innovative spintronic devices utilizing the unconventional conduction emerging from the quantum metric.