Transport through (Ga,Mn)As nanoislands: Coulomb-blockade and temperature dependence of the conductance

Abstract

We report on magnetotransport measurements of nanoconstricted (Ga,Mn)As devices showing very large resistance changes that can be controlled by both an electric and a magnetic field. Based on the bias voltage and temperature dependent measurements down to the millikelvin range we compare the models currently used to describe transport through (Ga,Mn)As nanoconstrictions. We provide an explanation for the observed spin-valve like behavior during a magnetic field sweep by means of the magnetization configurations in the device. Furthermore, we prove that Coulomb-blockade plays a decisive role for the transport mechanism and show that modeling the constriction as a granular metal describes the temperature and bias dependence of the conductance correctly and allows to estimate the number of participating islands located in the constriction.

5 pages, 3 figures, completed affiliations and corrected typos

References in corpus (4)

• Curie point singularity in the temperature derivative of resistivity in (Ga,Mn)As
• Control of magnetic anisotropy in (Ga,Mn)As by lithography-induced strain relaxation
• Magnetization-Switched Metal-Insulator Transition in a (Ga,Mn)As Tunnel Device
• Huge tunnelling anisotropic magnetoresistance in (Ga,Mn)As nanoconstrictions

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• On the origin of magnetism in (Ga,Mn)As: from paramagnetic through superparamagnetic to ferromagnetic phase
• Spin gating electrical current
• Hole sp3-character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches - newly found spin-unpolarized gap states of s-type below 1% of Mn
• Anisotropic magneto-capacitance in ferromagnetic-plate capacitors
• Double island Coulomb blockade in (Ga,Mn)As-nanoconstrictions