Strong-coupling theory of the universal linear temperature dependence
of the nodal Fermi velocity in layered cuprates
Phys. Rev. B, 78 (6):
060509(R) (2008)DOI: 10.1103/PhysRevB.78.060509
Abstract
We explain the recently observed linear temperature dependence of
the nodal Fermi velocity vF(T) in nearly optimally doped cuprates.
We argue that it originates from electron-electron interaction and
it is a fundamental property of an arbitrary two-dimensional (2D)
Fermi liquid. We consider a spin-fermion model with input parameters
extracted from the data, and we show that the T term is about 30%
at 300 K, in agreement with the data. We show that the sub-leading
term in vF(T) is a regular (and small) T2 correction. We also show
that at a 2kF quantum-critical point, temperature corrections to
the dispersion are singular.