Two distinct electronic species detected in magic-angle twisted bilayer graphene

“This had been hinted at experimentally before, but lacked direct evidence, which we have provided for the first time,” shares ICFO’s Dr. Rafael Luque Merino, first author of the article. One of the species corresponds to itinerant electrons, similar to the ‘usual’ free electrons. Such electrons can move across the material, carrying charge and heat. Due to their high mobility, and low effective mass, they are sometimes referred to as ‘light carriers’. The other species resides in highly localized orbitals and interact very strongly between them, which causes a drastic reduction of their mobility. Consequently, these ‘heavy carriers’ do not contribute significantly to charge and heat transport.

Researchers from ICFO, Princeton University, Donostia International Physics Center (DIPC), National Institute for Materials Science and Ludwig Maximilian University of Munich have detected two electronic ‘species’ coexisting in magic-angle twisted bilayer graphene. The technique, based on thermoelectric measurements, provides insight into the strongly-correlated phases of this condensed matter platform.“This had been hinted at experimentally before, but lacked direct evidence, which we have provided for the first time,” shares ICFO’s Dr. Rafael Luque Merino, first author of the article. One of the species corresponds to itinerant electrons, similar to the ‘usual’ free electrons. Such electrons can move across the material, carrying charge and heat. Due to their high mobility, and low effective mass, they are sometimes referred to as ‘light carriers’. The other species resides in highly localized orbitals and interact very strongly between them, which causes a drastic reduction of their mobility. Consequently, these ‘heavy carriers’ do not contribute significantly to charge and heat transport.

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