Researchers Observe Bistable Superlattice Switching in Quantum Material

By WSN Editorial TeamTech ReporterMarch 19, 20263 min read

A study reveals how a quantum material exhibits bistable switching, toggling between lattice states via electrostatic means.

Scientists from multiple institutions published a study in Nature on March 18, 2026, detailing bistable superlattice switching in monolayer TaIrTe4, a dual quantum spin Hall insulator. This switching occurs between two lattice configurations with different periodicities, where a long-period superlattice emerges spontaneously in the pristine monolayer.

What is Bistable Switching in This Context?

In the material, bistable switching allows the system to toggle between a standard lattice and a superlattice with a unit cell area differing by two orders of magnitude. This process is controlled non-volatilely through electrostatic tuning of low-energy electronic states, as observed in the experiments.

The research identifies two coupled instabilities: one in the lattice structure and another in the quantum spin Hall electrons. These instabilities enable the electrostatic control of lattice configurations, demonstrating a form of non-volatile memory in the material.

Experiments utilized linear and nonlinear transport measurements, Raman spectroscopy, and scanning tunnelling microscopy to probe the phenomenon. These methods revealed that the superlattice has a periodicity on the few-nanometre scale and remains stable across a wide doping range.

The superlattice persists for days and withstands temperatures above 70 K. Preliminary data also indicate the emergence of new insulating states at fractional superlattice fillings, which can be switched alongside the main superlattice.

This discovery builds on previous work in quantum materials, showing how electronic properties can influence structural changes. The study was conducted by a team of researchers from various institutions, as listed in the Nature article.