Original title: Initialization-free ultralow-power programmable spin-orbit torque logic devices enabled by chirally asymmetric switching
Qianbiao Liu, Lijun Zhu · September 2026
Modern artificial intelligence chips need faster, more efficient hardware. Scientists want to use spin logic, a method that computes using the magnetic spin of electrons instead of standard electrical charges. However, building a single device that can run all standard logic tasks without needing to be reset first has been difficult for more than two decades. To solve this, researchers built a device using a Ta/FeCoB two-layer structure. It works through chirally asymmetric switchingThe magnetization switches differently depending on the handedness of the magnetic texture, allowing direct programming., where magnetic states flip in an uneven, handed way guided by special internal magnetic fields. This single device successfully performs the complete set of 16 Boolean logic operationsBasic operations like AND, OR, NOT that process binary data (0s and 1s). using just three inputs. It operates without any initialization step and consumes an ultralow power of < 1 fJ/bit.
Imagine a combination lock that accepts a new code directly without needing to be reset to zero first. The same lock can be set to any of 16 different codes depending on which way you turn the dial. That saves time and eliminates the need for multiple locks. In this paper, the spin-orbit torque device uses the direction of the current to directly set any of the 16 Boolean logic operations without an initialization step, similar to how the lock accepts a new code based on the dial turn.
Current AI chips consume substantial power due to many logic gates. This single device performs all 16 Boolean operations with less than 1 femtojoule per bit, eliminating initialization steps and reducing energy use. It could enable more efficient, compact processors for artificial intelligence, from smartphones to data centers.
The cascading computing devices (half adder, full adders, selector) are only proposed, not experimentally demonstrated in this work. The single device demonstration is reported, but the abstract does not discuss potential challenges such as variability, temperature sensitivity, or large-scale integration. The power consumption of <1 fJ/bit is for the single device, and overhead for cascading is not addressed.
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Initialization-free ultralow-power programmable spin-orbit torque logic devices enabled by chirally asymmetric switching — Qianbiao Liu, Lijun Zhu
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.