"Spin and magnetic properties of the III-V group semiconductors" / "Propriedades magnéticas e de spin em semicondutores do grupo III-V"

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

We present the results of our investigations concerning MBE grown AlGaAs/GaAs parabolic quantum well (PQW) samples. We focused on the variation of the Landé g factor along the structure of the PQWs, which occur as a consquence of its dependence on the Al content on the alloy AlGaAs. The implications are studied by Hall and Shubnikov-de Haas measurements. Shubnikov-de Haas measurements at temperatures of the order of tenths to hundreds of milikelvin with variation of the tilt angle are shown to be an efficient method for the determination of the g factor. We could distinguish not only the alloy g factor, but its many body contribution (exchange contribution). On the other hand, Hall measurements exhibit an unusual behavior, which we prooved it has no relation neither to the well known "anomalous Hall effect", a characteristic of ferromagnetic materials, nor to a multi subband occupation effect. We atribute such behavior to a "spin valve effect", caused by the spatial variation of the g factor. Our observations allow us to idealize a "spin valve" transistor, without any ferromagnetic material in its structure.

ASSUNTO(S)

g factor hall effect fator g algaas spintronics efeito hall poços quânticos parabólicos semiconductors spintrônica parabolic quantum wells shubnikov-de haas effect semicondutores efeito shubnikov-de haas algaas válvula de spin spin valve

ACESSO AO ARTIGO

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