Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping

Details Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping

1998-07-02

arxiv.org/abs/cond-mat/9807046v1

Physics

Condensed Matter

Strongly Correlated Electrons

9 pages, 4 EPS figures, RevTeX

Scientific paper

10.1088/0953-8984/10/48/021

We analyze the two-dimensional spin-fermion model in the strong coupling regime relevant to underdoped cuprates. We recall the set of general sumrules that relate moments of spectral density and the imaginary part of fermion self-energy with static correlation functions. We show that two-pole approximation of projection method satisfies the sumrules for first four moments of spectral density and gives an exact upper bound for quasiparticle energy near the band bottom. We prove that non-crossing approximation that is often made in perturbative consideration of the model violates the sumrule for third moment of spectral density. This leads to wrong position of lowest quasiparticle band. On the other hand, the projection method is inadequate in weak coupling limit because of approximate treatment of kinetic energy term. We propose a generalization of projection method that overcomes this default and give the fermion self-energy that correctly behaves both in weak and strong coupling limits.

Affiliated with

Also associated with

No associations

Rating

Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Comparison of non-crossing perturbative approach and generalized projection method for strongly coupled spin-fermion systems at low doping will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-246235