Modulation of charge-density waves by superlattice structures
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Data
2006-05-01
Autores
Malvezzi, André Luiz [UNESP]
Paiva, Thereza
dos Santos, Raimundo R.
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Amer Physical Soc
Resumo
We discuss the interplay between electronic correlations and an underlying superlattice structure in determining the period of charge density waves (CDW's), by considering a one-dimensional Hubbard model with a repeated (nonrandom) pattern of repulsive (U > 0) and free (U=0) sites. Density matrix renormalization group diagonalization of finite systems (up to 120 sites) is used to calculate the charge-density correlation function and structure factor in the ground state. The modulation period can still be predicted through effective Fermi wave vectors k(F)(*) and densities, and we have found that it is much more sensitive to electron (or hole) doping, both because of the narrow range of densities needed to go from q(*)=0 to pi, but also due to sharp 2k(F)(*)-4k(F)(*) transitions; these features render CDW's more versatile for actual applications in heterostructures than in homogeneous systems.
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Physical Review B. College Pk: Amer Physical Soc, v. 73, n. 19, 4 p., 2006.