Hidden Charge 2e Boson: Experimental Consequences for Doped Mott Insulators

摘要

We show here that many of the normal state properties of the cuprates canresult from the new charge 2e bosonic field which we have recently (Phys. Rev.Lett. {\bf 99}, 46404 (2007) and Phys. Rev. B 77, 014512 (2008)) shown to existin the exact low-energy theory of a doped Mott insulator. In particular, the 1)mid-infrared band including the non-vanishing of the restricted f-sum rule inthe Mott insulator, 2) the $T^2$ contribution to the thermal conductivity, 3)the pseudogap, 4) the bifurcation of the electron spectrum below the chemicalpotential as recently seen in angle-resolved photoemission, 5) insulatingbehaviour away from half-filling, 6) the high and low-energy kinks in theelectron dispersion and 7) T-linear resistivity all derive from the charge 2ebosonic field. We also calculate the inverse dielectric function and show that it possessesa sharp quasiparticle peak and a broad particle-hole continuum. The sharp peakis mediated by a new charge e composite excitation formed from the binding of acharge 2e boson and a hole and represents a distinctly new prediction of thistheory. It is this feature that is responsible for dynamical part of thespectral weight transferred across the Mott gap. We propose that electronenergy loss spectroscopy at finite momentum and frequency can be used to probethe existence of such a sharp feature.