Pseudogap, superconducting energy scale, and Fermi arcs of underdoped cuprate superconductors

Abstract

Through the measurements of magnetic field dependence of specific heat in La2−xSrxCuO4 in zero temperature limit, we determined the nodal slope vΔ of the quasiparticle gap. It is found that vΔ has a very similar doping dependence of the pseudogap temperature T* or value Δp. Meanwhile the virtual maximum gap at (π,0) derived from vΔ is found to follow the simple relation Δq=0.46kBT* upon changing the doping concentration. This strongly suggests a close relationship between the pseudogap and superconductivity. It is further found that the superconducting transition temperature is determined by both the residual density of states of the pseudogap phase and the nodal gap slope in the zero temperature limit, namely, Tc≈βvΔγn(0), where γn(0) is the extracted zero temperature value of the normal state specific heat coefficient which is proportional to the size of the residual Fermi arc karc. This shows that the superconductivity may be formed by forming a new gap on the Fermi arcs near nodes below Tc. These observations mimic the key predictions of the SU(2) slave boson theory based on the general resonating-valence-bond picture.

Source-reported materials — not catalogue approval

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