Domain Walls Allow Dissipationless Chiral Edge Conduction of Electrons
March 20, 2018 | RIKENEstimated reading time: 2 minutes
By controlling magnetized patches within thin films of material, RIKEN researchers have created electronic channels that can carry a current without any loss of energy. This principle could eventually lead to extremely low-power electronic devices for storing and processing information.
The researchers’ work relies on a phenomenon called the quantum anomalous Hall effect (QAHE). This is related to the Hall effect, in which a magnetic field applied at right angles to an electrical current causes electrons in the current to drift to one side of the conductor, creating a voltage across the material.
The QAHE typically occurs in thin films at very low temperatures. Magnetic atoms within the material, rather than an external magnetic field, cause the same sort of electron drift.
Now, Kenji Yasuda of the University of Tokyo, along with colleagues at the RIKEN Center for Emergent Matter Science, has created a device that demonstrates how the QAHE could be exploited in computer chips.
Their device contained layers of bismuth antimony telluride, each a few nanometers thick, with alternating layers seeded with magnetic chromium atoms. Working at just half a degree Celsius above absolute zero, the researchers used a magnetic force microscope to apply a small magnetic field to it. They scanned the microscope over the device to create a magnetic patch, or domain, a few tens of micrometers wide. The edges of this area, known as domain walls, acted as magnetic boundaries: the magnetic orientation of the material pointed upward on one side of the wall and downward on the other side.
The researchers found that electrons, drifting due to the QAHE, could bounce along the domain wall in a process called chiral edge conduction. This happened because each domain wall had two ‘chiral edge states’, one on either side of the wall, which acted as channels to carry electrons in the same direction. “Since these electrons are never scattered by disorders or defects, they can flow without loss of energy,” says Yasuda.
The team built more of these devices and used the magnetic force microscope to create a range of different domain wall patterns that controlled how current flowed through the devices. By using the microscope to move the domain wall patterns around, they could also modify the performance of the devices.
The team now hopes to create chiral edge states at higher temperatures and control their position using an electric current. “These developments will be important steps for realizing electronic devices based on chiral edge states,” Yasuda comments.
Suggested Items
Walmart Acquires Vizio, Set to Overtake Samsung as the Largest TV Brand in the US
02/22/2024 | TrendForceUS retail giant Walmart announced on February 20, that it has acquired smart TV brand Vizio for US$2.3 billion, aiming to accelerate the growth of its advertising business: Walmart Connect. Since its launch in 2021, Walmart Connect has seen double-digit annual growth in both its online and offline retail media advertising ventures. Vizio has been expanding its device ecosystem and its SmartCast TV OS, boasting over 18 million active users, according to TrendForce.
Fiber Optic Cables Effective Way to Detect Tsunamis
02/16/2024 | University of MichiganFiber optic cables that line ocean floors could provide a less expensive, more comprehensive alternative to the current buoys that act as early warning systems for tsunamis, says a University of Michigan researcher.
EIPC Winter Conference 2024, Day 2: A Closer Look at Global Trends
02/14/2024 | Pete Starkey, I-Connect007The opening session of the second day’s conference proceedings focused on global PCB trends and was introduced and moderated by Dr. Michele Stampanoni, vice president of strategic sales and business development at Cicor Group in Switzerland. He opened the session with Dr. Hayao Nakahara’s knowledgeable and enlightening video presentation on the IC substrates industry.
IDTechEx Discusses Whether Fuel Cell Vehicles Will Succeed and What It Would Take
02/12/2024 | PRNewswireThe sales of hydrogen fuel cell cars have largely stalled from 2021 onwards, but does this mean there is no market for fuel cell electric vehicles (FCEVs) in the future, and what is required to make them a success? IDTechEx's report, "
Electronics Industry Mourns Loss of Colleague and Visionary Michael Ford
01/31/2024 | I-Connect007Sadly, longtime I-Connect007 columnist, industry visionary, and friend Michael Ford passed away Jan. 27. “In this time of sorrow, we can take solace in the knowledge that Michael leaves a great legacy of contribution to the electronics industry,” according to a statement from Aegis Software. Michael was senior director of emerging industry strategy at Aegis. He was a prolific writer and speaker whose work and ideas put him at the forefront of electronics manufacturing. Working for Aegis gave him the opportunity to apply his software for electronics manufacturing experience to further drive technology solution innovation.