Extended Data Fig. 4: Anomalies in the main excitonic properties.
From: An electronic microemulsion phase emerging from a quantum crystal-to-liquid transition
a, Near the density of \({n}_{* }\) = 0.9×1012 cm-2, a noticeable discontinuity in the derivative of the exciton/RP resonance energy with respect to electron density, \(d{E}_{X}/{dn}\) is observed, signifying a change in the slope of the exciton/RP resonance energy. b, A pronounced slope change of the oscillator strength is observed near the density of \({n}_{* }\) = 0.9×1012 cm-2. Reflectance contrast spectra measurements were performed under a light power of 0.7 nW at a base lattice temperature of 16 mK. The black arrows on the top x-axis and black dashed lines indicate the characteristic densities, \({n}_{{\rm{WC}}}\) and \({n}_{* }\). Linear decrease of the oscillator strength upon doping is represented by the grey dashed line. The measured excitonic properties are a convolution of the intrinsic properties of its electronic environment and the details of how the exciton couples to the electrons. In particular, the exciton is sensitive to the electronic compressibility. Non-analytic behavior of the compressibility at the microemulsion-liquid transition should therefore be expected to lead to rapid changes in the excitonic properties.
