Space-Charge-Limited van der Waals Spin Transistor

In the pursuit of control of electronic transport with both charge and spin degrees of freedom, we present a new device in the spin transistor family. Our device structure amalgamates vertical and lateral transport into a single device and uses a single material to reduce spin depolarization. This device makes use of a step edge between monolayer and bilayer regions in a semiconducting two-dimensional A-type antiferromagnet (AFM). The conductivity of this device can be modulated by both magnetic ordering of the bilayer region and the charge density in the bottom layer. Due to the low number of free carriers and small channel length, the current is dominated by space-charge-limited conduction (SCLC). The hallmark of SCLC is a superlinear dependence on the source-drain voltage, and this superlinear regime leads to giant TMR up to 3000%.

To understand the magnetic state ordering, we use scanning nitrogen vacancy magnetometry to correlate the evolution of the magnetic order, due electrostatic doping and magnetic field training, with the transport results, which illuminates the interplay between magnetic ordering and device conductance.