Crossover of Charge Fluctuations across the Strange Metal Phase Diagram

Understand

A normal metal exhibits a valence plasmon, which is a sound wave in its conduction electron density.

• The mysterious strange metal is characterized by non-Boltzmann transport and violates most fundamental Fermi liquid scaling laws.
• A fundamental question is: Do strange metals have plasmons? Using momentum-resolved inelastic electron scattering (M-EELS) we recently showed that, rather than a plasmon, optimally-doped Bi$_{2.1}$Sr$_{1.9}$Ca$_{1.0}$Cu$_{2.0}$O$_{8+x}$ (Bi-2212) exhibits a featureless, temperature-independent continuum with a power-law form over most energy and momentum scales [M.
• Mitrano, PNAS 115, 5392-5396 (2018)].