Gate control of magnon spin transport in unconventional magnon transistors based on the van der Waals antiferromagnet CrPS₄

Magnon-based spintronic devices require the modulation of magnon spin transport for their operations. We provide a proof-of-principle of an unconventional two-terminal nonlocal magnon transport device where the same contact is simultaneously used as injector and gate and an unconventional three-terminal nonlocal magnon transport device where the gate is positioned outside the magnon transport channel. In these devices we modulate the diffusive magnon transport of incoherent magnons in the van der Waals antiferromagnet Chromium thiophosphate, CrPS4. The nonlocal signals generated electrically by spin injection via the spin Hall effect (SHE) and thermally via the spin Seebeck effect are altered by a modulator electrode. The current through the modulator increases or decreases the magnon chemical potential via the SHE and changes the magnon temperature through Joule heating. We achieve up to ηSHE1ω=25%/mA and ηSHE2ω=16%/mA modulation efficiencies for the electrically and thermally generated magnon spin transport, respectively, for CrPS4 in the collinear state at in-plane fields >7 T at a temperature of 25 K.