Half-Metal–Spin-Gapless-Semiconductor Junctions as a Route to the Ideal Diode

Conventional semiconductor diodes have a junction barrier, and thus a threshold voltage, which gives rise to heat dissipation. The authors propose a diode concept based on half-metallic magnets (HMMs) and spin-gapless semiconductors (SGSs). The HMM-SGS junction does not have a barrier and behaves like an Ohmic contact under forward bias, while for reverse bias the current is blocked by spin-dependent filtering of the electrons. Thus the proposed diode exhibits a threshold voltage of zero, linear $I\ensuremath{-}V$ characteristics, and much higher current-drive capability. The authors provide a detailed description of the concept and give proof of principle by quantum transport calculations.