Spectral functions of lightly doped antiferromagnets using dressed hole operators
- Instituto de Fisica Rosario, Avenida 27 de Febrero 210 bis, 2000 Rosario (Argentina)
- Department of Physics and National High Magnetic Field Lab, Florida State University, Tallahassee, Florida 32306 (United States)
Literature addressing the existence of hole pockets in experiments for the high-T{sub c} cuprates and in theoretical analysis of electronic models of correlated electrons is reviewed. It is argued that the issue is not conclusively resolved, both in theory and experiments. The apparently large Fermi surface observed in numerical studies of the doped Hubbard and t-J models suggests the presence of 1{minus}x carriers (with x the concentration of holes). However, this is in contradiction with results obtained in similar calculations for the Drude weight which scales with x at low doping. To address such a paradox, {ital dressed} operators are here used. Their spectral decomposition A({bold k},{omega}) is analyzed specially using the t-J model on ladders, but considering also chains and two-dimensional (2D) clusters. The results are contrasted against those obtained with the standard bare operators. It is concluded that substantial changes in the spectral weight can occur by replacing the bare hole creation operator by its dressed version. Apparently large Fermi surfaces can turn into small ones by working with quasiparticle (qp) operators that represent accurately the state of one hole. Thus, large Fermi surfaces in angle-resolved photoemission (ARPES), obtained by the sudden removal of an electron, may not be in contradiction with a visualization of the normal state of lightly doped antiferromagnets as composed of a gas of spin polarons with energies approximately obtained from the rigid band doping of the half-filled dispersion. The coexistence of a large Fermi surface in ARPES with, e.g., a holelike Hall coefficient seems possible in systems with strong correlations. In this paper the expression hole pocket is used as representing a large accumulation of spectral weight centered at {bold k}=({plus_minus}{pi}/2,{plus_minus}{pi}/2) generated by antiferromagnetic correlations in 2D clusters, or in analogous positions for ladders and chains. (Abstract Truncated)
- OSTI ID:
- 544501
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 55, Issue 21; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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