Quantum Physicists Find Paradoxical Material a Mashup of Three Different Phases at Once – “This Is Uncharted Territory” ~ SCRIBBLE SPHERE

Quantum Physicists Find Paradoxical Material a Mashup of Three Different Phases at Once – “This Is Uncharted Territory”

Writer: HimAnshu

Date :Jan 24,2022

‘Geometric frustration’ can cause the electrons in materials with atoms arranged in a triangular pattern to organize in three competing ways simultaneously, reveals a new computational study led by researchers at the Flatiron Institute.

Materials that look like mosaics of triangular tiles at the atomic level sometimes have paradoxical properties, and quantum physicists have finally found out why.

Using a combination of cutting-edge computational techniques, the scientists found that under special conditions, these triangular-patterned materials can end up in a mashup of three different phases at the same time. The competing phases overlap, with each wrestling for dominance. As a result, the material counterintuitively becomes more ordered when heated up, the scientists reported in Physical Review X.

“This is uncharted territory,” says study lead author Alexander Wietek, a research fellow at the Flatiron Institute’s Center for Computational Quantum Physics (CCQ) in New York City. “Experimentalists had seen these peculiar properties, but they didn’t know what the individual electrons in the materials were doing. Our role as theorists is to understand from the bottom up what’s actually happening.”

The findings could help researchers develop materials for future electronics, Wietek says. This is because the odd properties, he says, are indicative of an elusive state of matter sought for potential use in error-correcting quantum computing.

Wietek’s co-authors on the new paper include CCQ research fellow Riccardo Rossi, CCQ research scientist Miles Stoudenmire and CCQ director Antoine Georges.

Under certain conditions, electrons in a triangular lattice exhibit odd behavior. New research shows that the electrons attempt to organize themselves simultaneously in three competing ways. This animation demonstrates each order: alternating columns, angles separated by 120 degrees and a twisting pattern in three dimensions. Credit: Lucy Reading-Ikkanda/Simons Foundation.

The researchers investigated how the electrons in the materials behave. Electrons determine almost all a material’s properties, from magnetism to conductivity and even color.

Grasping the collective behavior of the electrons is a monumental task. When two particles interact, they become quantum mechanically entangled with one another. Even once they’re separated, their fates remain entwined, and they can’t be treated separately.

The behavior of electrons in a material depends on the layout of the atoms, and the triangular lattice arrangement is fascinating. That’s because electrons have a spin, which can point either up or down. An electron might, for instance, want to have a different spin direction than its neighbors. But in a triangle with three atoms and only two spin directions, “someone is always going to be unhappy,” Wietek says. “This causes the system to fluctuate because it doesn’t really know what to do.” Quantum physicists call this ‘geometric frustration.’

Experimentalists had previously observed unexpected behavior in materials with triangular lattices, such as in twisted layers of tungsten diselenide or boron nitride. Wietek and his colleagues investigated by setting up a simple model to see what the electrons were doing. Their model is a grid of triangles, with each connecting point serving as a site that electrons can inhabit. Each site can host up to two electrons so long as they have opposite spins. In the model, there were as many electrons as sites.