Spin and charge gaps in the one-dimensional Kondo-lattice model with Coulomb interaction between conduction electrons

The density-matrix renormalization-group method is applied to the one-dimensional Kondo-lattice model with the Coulomb interaction between the conduction electrons. The spin and charge gaps are calculated as a function of the exchange constant (Formula presented) and the Coulomb interaction (Formula presented). It is shown that both the spin and charge gaps increase with increasing (Formula presented) and (Formula presented). The spin gap vanishes in the limit of (Formula presented) for any (Formula presented) with an exponential form, (Formula presented). The exponent, (Formula presented), is determined as a function of (Formula presented). The charge gap is generally much larger than the spin gap. In the limit of (Formula presented), the charge gap vanishes as (Formula presented) for (Formula presented) but for a finite (Formula presented) it tends to a finite value, which is the charge gap of the Hubbard model.