Weak phase stiffness and nature of the quantum critical point in underdoped cuprates

Abstract

We demonstrate that the zero-temperature superconducting phase diagram of underdoped cuprates can be quantitatively understood in the strong binding limit, using only the experimental spectral function of the "normal" pseudogap phase without any free parameter. In the prototypical (La1-xSrx)2CuO4, a kinetics-driven d-wave superconductivity is obtained above the critical doping δc∼5.2%, below which complete loss of superfluidity results from local quantum fluctuation involving local p-wave pairs. Near the critical doping, an enormous mass enhancement of the local pairs is found responsible for the observed rapid decrease of phase stiffness. Finally, a striking mass divergence is predicted at δc that dictates the occurrence of the observed quantum critical point and the abrupt suppression of the Nernst effects in the nearby region.