Lowenergy properties of fermions with singular interactions
Abstract
We calculate the fermion Green function and particlehole susceptibilities for a degenerate twodimensional fermion system with a singular gauge interaction. We show that this is a strongcoupling problem, with no small parameter other than the fermion spin degeneracy N. We consider two interactions, one arising in the context of the tJ model and the other in the theory of halffilled Landau level. For the fermion selfenergy we show that the qualitative behavior found in the leading order of perturbation theory is preserved to all orders in the interaction. The susceptibility χ_{Q} at a general wave vector Q≠2p_{F} retains the Fermiliquid form. However, the 2p_{F} susceptibility χ_{2pF} either diverges as T>0 or remains finite but with nonanalytic wavevector, frequency, and temperature dependence. We express our results in the language of recently discussed scaling theories, give the fixedpoint action, and show that at this fixed point the fermiongaugefield interaction is marginal in d=2, but irrelevant at low energies in d>=2.
 Publication:

Physical Review B
 Pub Date:
 November 1994
 DOI:
 10.1103/PhysRevB.50.14048
 arXiv:
 arXiv:condmat/9406024
 Bibcode:
 1994PhRvB..5014048A
 Keywords:

 71.27.+a;
 11.15.q;
 74.20.Mn;
 73.40.Hm;
 Strongly correlated electron systems;
 heavy fermions;
 Gauge field theories;
 Nonconventional mechanisms;
 Condensed Matter
 EPrint:
 21 pages, uuencoded LATEX file with included Postscript figures, RU