Researchers at Monash University have developed a groundbreaking structure that liberates new possibilities for ultra-efficient electronics and solar technology, using a quantum anomalous Hall (QAH) insulator.
The research team at Monash University, Australia has designed a heterostructure by placing an ultra-thin topological insulator between two 2D ferromagnetic insulators. This “quantum sandwich” exhibits the QAH effect, allowing current to flow without loss along quantized edges, which has major implications for low-energy electronics and advanced photovoltaic systems. These developments are particularly relevant for industries focused on energy efficiency, such as semiconductor manufacturing and renewable energy sectors, which require innovative materials to reduce power consumption and improve performance.
The quantum anomalous Hall effect is a result of combining magnetic materials with topological insulators, creating a state where electrical resistance is nearly zero along the edges. In this configuration, ferromagnetic layers serve as the “bread,” and the topological insulator, known for its unusual electronic properties, forms the “filling.” Together, these materials enable lossless transport of electrical current, a key step toward next-generation electronics.
The specific architecture involves a 2D ferromagnetic material, MnBi2Te4, layered on both sides of Bi2Te3, a well-known topological insulator. This structure demonstrated a robust QAH phase, with a large bandgap exceeding room temperature thermal energy, crucial for real-world applications. “We observed strong, hexagonally-warped massive Dirac fermions and a bandgap of 75 meV”, said Qile Li, lead researcher & PhD candidate, Monash University, Australia.Â
The study confirmed the magnetic origin of this gap through various methods, including observations of the bandgap’s behavior above the Curie temperature. These findings offer insights into how magnetic proximity effects in topological insulators can be harnessed for high-temperature applications, according to Dr. Mark Edmonds, Project leader, Monash University, Australia.
Experimental work was carried out at Lawrence Berkeley National Laboratory, where the heterostructures were grown and analyzed. “Although we cannot directly observe the QAH effect using angle-resolved photoemission spectroscopy, we could probe the size of the bandgap and confirm it is magnetic in origin,” said Dr. Edmonds.
This innovative approach, avoiding the complications of magnetic dopants in traditional systems, holds promise for advancing lossless electronic transport in future devices, with potential applications spanning across low-energy electronics and solar technologies.
