The widths of single-particle states of anisotropic, strongly correlated electron systems in solids

The damping gamma(epsilon) of electron states in crystals is investigated b eyond the phase transition point related to a rearrangement of the Fermi su rface. Attention is focused on the alteration of the standard Landau theory due to the emergence of a flat portion in the spectrum xi(p) of single-par ticle excitations as a result of the rearrangement. In the limit epsilon -- > 0, the width gamma(epsilon) of the states in the region of the Brillouin zone where the dispersion of xi(p) is of an ordinary order of magnitude is found to depend on epsilon almost linearly, in contrast to the Fermi-liquid -theory result gamma(epsilon) similar to epsilon(2). (C) 1999 American Inst itute of Physics. [S0021-3640(99)01123-8].