Theory of the leading edge gap in underdoped cuprates

Abstract

We present the theory of the leading edge gap in the normal state of underdoped high-$T_c$ materials. The consideration is based on a magnetic scenario for cuprates. We show that as doping decreases, the increasing interaction with paramagnons gives rise to a near destruction of the Fermi liquid and this in turn yields precursors to $d-$wave pairing. We argue that the leading edge gap at $\sim 30 meV$ and a broad maximum in the spectral function at $\sim150 meV$ are byproducts of the same physical phenomenon.