Charge and spin fluctuations at the collapse of the pseudogap in a cuprate superconductor

Understanding high-temperature superconductivity in cuprates remains a challenging problem. One approach is to characterise the evolution of the spin and charge excitations with doping and correlate these with other physical properties such as resistivity and heat capacity. We have had success in this regard using LET to demonstrate the existence of very-low-energy collective spin excitations for a sample with doping, p, greater than the critical doping where the so-called pseudogap disappears. Here we propose the measure at the critical doping of p*=0.19 where we have reason to think that both the spin and charge excitations will have the lowest characteristic energies. Our results may provide a framework to understand the strange metal (linear) behaviour observed in resistivity for this composition.