Orbital Magnetic Field Driven Metal-Insulator Transition in Strongly Correlated Electron Systems
Magnetic fields drastically alter the electronic spectrum, producing a fractal structure known as the Hofstadter butterfly. Our paper demonstrates that this modification of the spectrum induces a phase transition from a Mott insulator to a metal. The image illustrates how the butterfly drives the motion of electrons, thereby transforming an insulator into a metal.
Lead author and TYC member Goerg Rohringer, and his co-author Anton Markov, demonstrate that a magnetic field can transform a Mott insulator—where electron motion is strongly suppressed due to Coulomb repulsion—into a conductor.
In the classical world, a magnetic field merely bends the trajectories of charged particles without altering their energy. In the quantum realm, however, a magnetic field intricately modifies the material’s band structure, producing a fractal pattern known as the Hofstadter butterfly.
The authors show that this transformation enhances electron mobility sufficiently to turn a Mott insulator into a metal. Their findings are motivated by recent experiments in which such effects have been observed under strong magnetic fields in a range of correlated materials and may potentially spur new technological developments in this area of research.
Authors: Georg Rohringer, Anton Markov