Abstract
Using tunneling spectroscopy, we show that pseudogaps emerge in strongly correlated, two-dimensional electron liquids in quantum wells that are tuned near a quantum critical point. Coherence peaks emerge at low temperatures in quantum wells embedded in antiferromagnetic that remain itinerant to the lowest thickness. Quantum wells embedded in ferrimagnetic that become ferromagnetic at low temperatures show no indication of quasiparticle coherence. They undergo a symmetry-lowering metal-to-insulator transition at the lowest thicknesses that coincides with a vanishing single-particle density of states (DOS) around the Fermi level. Both types of quantum wells show a power-law depletion of the DOS at high energies. The results show that the different pseudogap behaviors are closely correlated with the type of magnetism in the proximity of the quantum wells and thus provide insights into the microscopic mechanisms.
- Received 21 November 2015
DOI:https://doi.org/10.1103/PhysRevLett.117.046402
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