1011.3206 (Moshe Dayan)

The Origin of the Pseudogap in Underdoped HTSC    [PDF]

Moshe Dayan

Here the Origin of the pseudogap in HTSC is attributed to the modulated
antiferromagnetic (AFM) phase, whose preliminary version has been sketched
recently by the present author [1]. Starting from the t-J Hamiltonian, I show
that the formal failure of the perturbation theory leads to a transformation to
the pseudogap phase. This phase is characterized by the aggregation of the
holes into rows and columns, which in turn results in two internal fields. The
first is the modulated AFM field, whose main evidence comes from Neutron
scattering experiments. The second internal field is made up by the
checkerboard charge density waves that have been observed by Scanning Tunneling
Measurements. The present paper deals mainly with the internal field of the
first type, and discusses the second type only tentatively. Formalism is
derived that yields the ground state, the internal field, the Hamiltonian, and
the propagators of the condensed phase. Our results resolve the presumably
inherent self contradictory concept of pseudogap. It is shown that the
excitation energy spectrum is gapless despite the order parameter that is
inherent to the condensed system. In addition, it is shown qualitatively that
our model predicts "Fermi surface" that is in agreement with experiment.

View original: http://arxiv.org/abs/1011.3206