Voltage-Controlled Spin Selection in a Magnetic Resonant Tunneling Diode

We have fabricated all $\mathrm{I}\mathrm{I}\mathrm{\text{−}}\mathrm{V}\mathrm{I}$ semiconductor resonant tunneling diodes based on the $(\mathrm{Z}\mathrm{n},\mathrm{M}\mathrm{n},\mathrm{B}\mathrm{e})\mathrm{S}\mathrm{e}$ material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and could be the first step towards a voltage controlled spin filter.