By Josh Perry, Editor
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Researchers at the Delft (Netherlands) University of Technology (TU Delft) have discovered that nano-electronic phase transitions in nickelates, a class of solid-state materials that can phase transition from conducting to insulating behavior, can be controlled by laser light.

TU Delft researchers showed that nickelate phase transitions can be controlled with light. (Tu Delft)

According to a report from TU Delft, previous research demonstrated how the metal-insulator transition worked but now the researchers have shown that this transition can also be controlled.

Ultrafast laser pulses were directed at a sample of neodymium nickelate (NdNiO₃), which raised the temperature from 150-152 Kelvin for brief amount of time. This small temperature rise was enough to cause the transition from insulating to conducting.

Increasing the strength of the laser allowed the scientists to control the physical properties of the material, which was enhanced by the hysteresis of the nickelate. Since the transition from one property to another happen at different temperatures, the material can be locked into a phase (similar to how thermostats are controlled).

Researchers believe that this development could be used to create conductivity switches for circuits and novel electronics.

The research was recently published in Physical Review Materials. The abstract read:

“Strongly correlated materials show unique solid-state phase transitions with rich nanoscale phenomenology that can be controlled by external stimuli. Particularly interesting is the case of light–matter interaction in the proximity of the metal–insulator transition of heteroepitaxial nickelates.

“In this work, we use near-infrared laser light in the high-intensity excitation regime to manipulate the nanoscale phase separation in NdNiO3. By tuning the laser intensity, we can reproducibly set the coverage of insulating nanodomains, which we image by photoemission electron microscopy, thus semipermanently configuring the material state.

“With the aid of transport measurements and finite element simulations, we identify two different timescales of thermal dynamics in the light–matter interaction: a steady-state and a fast transient local heating.

“These results open interesting perspectives for locally manipulating and reconfiguring electronic order at the nanoscale by optical means.”