A group of physicists at Florida State University (FSU) has identified a new state of matter involving electrons, potentially opening avenues for advancements in quantum computing and other technologies. The team, which includes Dirac Postdoctoral Fellow Aman Kumar, Associate Professor Hitesh Changlani, and Assistant Professor Cyprian Lewandowski from the National High Magnetic Field Laboratory, published their findings in npj Quantum Materials.
Their research focused on the conditions that allow electrons to arrange themselves into a solid crystalline lattice but also “melt” into a liquid state. This phase is known as a generalized Wigner crystal. Unlike traditional Wigner crystals—which only display triangular lattice structures—these generalized versions can form different shapes such as stripes or honeycomb patterns.
“In our study, we determined which ‘quantum knobs’ to turn to trigger this phase transition and achieve a generalized Wigner crystal, which uses a 2D moiré system and allows different crystalline shapes to form, like stripes or honeycomb crystals, unlike traditional Wigner crystals that only show a triangular lattice crystal,” Changlani said.
The researchers used FSU’s Research Computing Center and the National Science Foundation’s ACCESS program to perform extensive calculations and simulations. These efforts employed numerical techniques including exact diagonalization, density matrix renormalization group methods, and Monte Carlo simulations. By simplifying complex quantum information through advanced algorithms, the team was able to draw meaningful conclusions about electron behavior.
“We’re able to mimic experimental findings via our theoretical understanding of the state of matter,” Kumar said. “We conduct precise theoretical calculations using state-of-the-art tensor network calculations and exact diagonalization, a powerful numerical technique used in physics to collect details about a quantum Hamiltonian, which represents the total quantum energy in a system. Through this, we can provide a picture for how the crystal states came about and why they’re favored in comparison to other energetically competitive states.”
The team also reported observing an unusual “pinball phase,” where some electrons remain fixed while others move freely within the material—a combination of insulating and conducting properties not previously seen at this electron density.
“This pinball phase is a very exciting phase of matter that we observed while researching the generalized Wigner crystal,” Lewandowski said. “Some electrons want to freeze and others want to float around, which means that some are insulating and some are conducting electricity. This is the first time this unique quantum mechanical effect has been observed and reported for the electron density we studied in our work.”
Lewandowski explained why these discoveries are important: “What causes something to be insulating, conducting or magnetic? Can we transmute something into a different state? We’re looking to predict where certain phases of matter exist and how one state can transition to another — when you think of turning a liquid into gas, you picture turning up a heat knob to get water to boil into steam. Here, it turns out there are other quantum knobs we can play with to manipulate states of matter, which can lead to impressive advances in experimental research.”
By tuning these so-called “quantum knobs,” scientists hope they can drive transitions between solid and liquid electronic phases. Understanding these processes could help develop new technologies in areas such as spintronics—a field aimed at improving nano-electronic devices by enhancing memory capacity while reducing power use—and next-generation superconductors for energy systems or medical imaging.
The FSU team aims to continue exploring how electrons cooperate within materials with hopes that their work will contribute further breakthroughs in quantum science and technology.
More information about ongoing research at FSU’s Department of Physics is available at https://physics.fsu.edu/. Details on projects led by the National High Magnetic Field Laboratory can be found at https://nationalmaglab.org/.
