Metal-insulator transition in the one-dimensional Kondo lattice model

Дата и время публикации : 1998-03-09T16:49:59Z

Авторы публикации и институты :
K. Le Hur

Ссылка на журнал-издание: Phys. Rev. B 58 1998 10261.
Коментарии к cтатье: 14 pages, 6 figures, (added Latex file)
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el

Краткий обзор статьи: We study the usual one-dimensional Kondo lattice model (1D KLM) using the non-Abelian bosonization formalism. At half-filling, we obtain a Kondo insulator with a gap in both charge and spin excitations which varies quite linearly with the Kondo exchange $J_K$. It consists of a Spin Density Glass state, or a $q=pi$ spin density wave weakly pinned by a nearly antiferromagnetically ordered spin array. We will analyze the stability of the SDG state in presence of randomness. We will compare these results with those obtained in the one-dimensional Heisenberg-Kondo lattice model (1D HKLM) where the spins are coupled through a large Heisenberg exchange. Away from half-filling, the system is metallic and yields a very small spin gap which is equal to the one-impurity Kondo gap $T_k^{(imp)}$. Unlike the one-impurity Kondo model, we will show why this Kondo phase cannot rule the fixed point of the 1D KLM, away from half-filling. We will rather obtain a normal heavy-fermion state controlled by the energy scale $T_{coh}sim (T_k^{(imp)})^2/t$ (t is the hopping term) with a quite long-range antiferromagnetic polarization. It is important to notice that both the SDG state and the normal heavy-fermion state are susceptible to occur near a magnetic instability.

Category: Physics