Fig. 3: Doping dependence of Fano interference in La2−xSrxCuO4.
From: Fano interference between collective modes in cuprate high-Tc superconductors
The Fano interference of the driven superconducting fluctuations is identified by the dip in THG intensity (I3ω) concomitant with the negative jump in THG phase (Φ3ω) at the temperature denoted by Tπ (red solid line). The dip-peak feature in I3ω(T) near and above Tπ gives the typical asymmetrical line shape associated with the Fano resonance/interference, compounded by an additional superconducting screening factor9,21. a–e Temperature dependence of I3ω (blue squares) and Φ3ω (red dots) in a x ~0.12 (UD26), b x ~0.16 (OP43), c x ~0.25 (OD44), d x ~0.30 (OD30), e x ~0.35 (OD28). The peak terahertz driving field strength used for these measurements are a ~10 kV/cm, b ~25 kV/cm, c ~25 kV/cm, d ~25 kV/cm, and e ~20 kV/cm. f Temperature dependence of Φ3ω from all five samples plotted on the reduced temperature (T/Tc) scale. The anti-resonance becomes increasingly broadened with hole-doping, indicating a broadening of the coupled mode on the overdoped side.
