DC-transport properties of ferromagnetic (Ga,Mn)As semiconductors

T. Jungwirth, Jairo Sinova, K.Y. Wang, K.W. Edmonds, R.P. Campion, B.L. Gallagher, C.T. Foxon, Qian Niu, A.H. MacDonald

We study the dc transport properties of (Ga,Mn)As diluted magnetic semiconductors with Mn concentration varying from 1.5% to 8%. Both diagonal and Hall components of the conductivity tensor are strongly sensitive to the magnetic state of these semiconductors. Transport data obtained at low temperatures are discussed theoretically within a model of band-hole quasiparticles with a finite spectral width due to elastic scattering from Mn and compensating defects. The theoretical results are in good agreement with measured anomalous Hall effect and anisotropic longitudinal magnetoresistance data. This quantitative understanding of dc magneto-transport effects in (Ga,Mn)As is unparalleled in itinerant ferromagnetic systems [1].

Experimental (filled symbols) AMR coefficients and theoretical data obtained assuming As-antisite compensation (open symbols) and Mn-interstitial compensation (semi-filled symbols).
Here, AMR_op = [σ_xx(M || ẑ ) - σ_xx(M || x̂ )] / σ_xx(M || x̂ ) and AMR_ip = [σ_xx(M || ŷ ) - σ_xx(M || x̂ )] / σ_xx(M || x̂ ).

[1] Appl. Phys. Lett. 83, 320 (2003): doi:10.1063/1.1590433