Control of ferromagnetism by manipulating the carrier wavefunction in ferromagnetic semiconductor (In,Fe)As quantum wells

We demonstrated the control of ferromagnetism in a surface quantum well containing a 5 nm-thick n-type ferromagnetic semiconductor (FMS) (In, Fe) As layer sandwiched between two InAs layers, by manipulating the carrier wavefunction. The Curie temperature (T-C) of the (In,Fe) As layer was effectively changed by up to 12K (Delta T-C/T-C = 55%). Our calculation using the mean-field Zener theory reveals an unexpectedly large s-d exchange interaction in (In, Fe) As. Our results establish an effective way to control the ferromagnetism in quantum heterostructures of n-type FMSs, as well as require reconsideration on the current understanding of the s-d exchange interaction in narrow gap FMSs. (C) 2014 AIP Publishing LLC.