Spin- and charge-excitation gaps in the one-dimensional periodic Anderson model

T. Nishino and Kazuo Ueda
Phys. Rev. B 47, 12451 – Published 15 May 1993
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Abstract

Spin and charge excitations in the one-dimensional periodic Anderson model at half filling are studied in the entire range of the Coulomb interaction U. It is confirmed by exact numerical diagonalization of up to eight sites that an excitation gap exists for any U. In the strong-coupling region, both the spin-excitation gap Δs and charge-excitation gap Δc decrease with increasing U. A finite-size scaling shows that Δs decreases exponentially as a function of U which is consistent with the spin gap in the Kondo-lattice model. The charge gap Δc decreases much more slowly than the spin gap. The ratio between the two gaps, R=Δc/Δs, increases monotonically from unity and diverges in the strong-coupling limit: it appears to be a useful quantity for measuring the strength of electron correlation in a Kondo insulator.

  • Received 7 December 1992

DOI:https://doi.org/10.1103/PhysRevB.47.12451

©1993 American Physical Society

Authors & Affiliations

T. Nishino

  • Physics Department, College of General Education, Tohoku University, Sendai 980, Japan
  • Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Kazuo Ueda

  • Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

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Issue

Vol. 47, Iss. 19 — 15 May 1993

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