Physicists have uncovered an in-plane Hall response that overturns a century-old assumption about how this famous electrical effect works. The discovery could eventually make multidirectional magnetic sensing possible with one tiny device.
Scientists at Carnegie Mellon University have identified an unexpected form of the Hall effect that challenges a long-standing assumption about how electronic materials react to magnetic fields.
The finding expands scientists’ understanding of the Hall effect, a fundamental phenomenon used to study the electrical and magnetic properties of materials.
Published in Nature Materials, the work could eventually help researchers develop simpler and more flexible magnetic sensors for applications including electronics, transportation, and medical imaging.
A Century-Old Physics Effect
The Hall effect has been an important tool in physics for more than a century. In 1879, Edwin Hall discovered that when a magnetic field is applied perpendicular to a material carrying an electric current, the moving charges inside are deflected, creating a measurable voltage.
That signal can reveal several important properties of a material. Scientists can use it to determine whether current is being carried by negative or positive charges, estimate how many charge carriers are moving through the material, and measure how easily they travel.
Today, Hall effect sensing is widely used in technologies ranging from automobiles to computer keyboards.
Researchers in Carnegie Mellon’s Department of Physics, working in the Lab for Investigating Quantum Materials, Interfaces and Devices (LIQUID), have now demonstrated a previously unconfirmed form of the effect.
“For a long time, people thought the Hall effect only worked when the magnetic field was applied perpendicular to the plane of the film. We’ve shown that that’s not true — you can also get a response when the field is in-plane,” said Simranjeet Singh, an associate professor of physics.
Detecting Magnetism in More Than One Direction
The discovery broadens how the Hall effect can be used because it shows that a magnetization-dependent Hall response can occur in more than one direction.
That capability could help physicists study complicated magnetic and topological structures in condensed matter systems. In simple terms, researchers may be able to use the same basic phenomenon to probe how magnetism behaves along multiple directions inside advanced materials.
“Beyond fundamental importance, this discovery can enable novel planar device architectures and sensor types, such as vector magnetometry, via measuring the out-of-plane and in-plane anomalous Hall effect signals in the same device,” Singh said.
From Theory to Experimental Proof
Scientists had previously proposed the possibility of an in-plane anomalous Hall effect, but no experiment had successfully demonstrated it.
“People proposed it and ideas were out there, but it’s very difficult to make a magnetic material with the right symmetry to do it,” Singh said. “What we did was we found a material with the right symmetry, and we made it magnetic.”
To create the tiny devices needed for the study, Singh worked with Jyoti Katoch, an associate professor of physics who specializes in fabricating devices from two-dimensional quantum materials.
The research team, which also included postdoctoral researchers I-Hsuan Kao and Ravi Kumar, began with tantalum iridium telluride (TaIrTe4). This material has the crystalline symmetry needed to produce a multidimensional Hall effect.
The researchers reduced it to only a few atomic layers in thickness and then paired it with a magnetic layer, Cr2Ge2Te6 (CGT).
Because the two materials sit extremely close together, magnetism from the magnetic layer can influence the normally nonmagnetic layer. This gives the TaIrTe4 magnetic properties while allowing it to retain its distinctive electronic behavior.
“This truly demonstrates the power of building atomically precise heterostructures of emergent two-dimensional quantum materials to obtain on-demand electronic and magnetic properties,” Katoch said.
One Tiny Device, Multiple Magnetic Axes
Inside the atomically thin devices, the researchers detected both the conventional Hall signal and a second, unconventional signal tied to magnetization within the plane of the material.
Practically, that means a single ultrathin device can detect magnetic fields along more than one axis.
“We have broadened the potential application of these materials,” Singh said. “You can do multidimensional magnetic sensing with one sensor only. Before, you needed to put two sensors to measure the magnetic field in two directions.”
The result could eventually simplify certain magnetic sensing systems by allowing one device to perform measurements that previously required multiple sensors.
Explaining the Unusual Hall Response
To understand why the new effect appears, Shubhayu Chatterjee, an assistant professor of physics, performed theoretical modeling.
His work focused on how the symmetry of the combined materials changes when TaIrTe4 is paired with CGT, and how those changes allow the unusual Hall response to emerge.
“We found that the reduced symmetry due to pairing with CGT allows additional spin-orbit coupling at the interface. These spin-orbit coupling terms are crucial for the in-plane anomalous Hall effect to emerge once CGT becomes ferromagnetic at low temperatures. While certain features of the observed anomalous Hall effect signal are consistent with an intrinsic origin, a detailed characterization of few-layered TaIrTe4 is needed to nail down the precise mechanism,” Chatterjee said.
Spin-orbit coupling describes an interaction between an electron’s motion and its quantum spin. In this case, the interface between the two materials appears to create the conditions needed for the unusual in-plane Hall response.
Toward Practical Magnetic Sensors
The LIQUID team is now investigating other material combinations that might produce the same unconventional Hall behavior.
Researchers are also testing how the device performs at room temperature. Demonstrating a strong room-temperature response would be an important step toward turning the phenomenon into practical sensing technology.
Reference: “In-plane anomalous Hall effect in a low-dimensional system” by I-Hsuan Kao, Ravi Kumar Bandapelli, Zhenhong Cui, Shuchen Zhang, Jian Tang, Tiema Qian, Souvik Sasmal, Aalok Tiwari, Mei-Tung Chen, Raghvendra Posti, Rahul Rao, Jiahan Li, James H. Edgar, Kenji Watanabe, Takashi Taniguchi, Ni Ni, Su-Yang Xu, Qiong Ma, Shubhayu Chatterjee, Jyoti Katoch and Simranjeet Singh, 28 May 2026, Nature Materials.
DOI: 10.1038/s41563-026-02611-9
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1 Comment
Physicists have uncovered an in-plane Hall response that overturns a century-old assumption about how this famous electrical effect works. The discovery could eventually make multidirectional magnetic sensing possible with one tiny device.
VERY GOOD.
May I ask physicists:
1. Are the various assumptions in mainstream physics scientific?
2. Are you uncovering a assumption or a methodological flaw?