Electrically switchable van der Waals magnon valves

Abstract

Van der Waals magnets have emerged as a fertile ground for the exploration of highly tunable spin physics and spin-related technology. Two-dimensional (2D) magnons in van der Waals magnets are collective excitation of spins under strong confinement. Although considerable progress has been made in understanding 2D magnons, a crucial magnon device called the van der Waals magnon valve, in which the magnon signal can be completely and repeatedly turned on and off electrically, has yet to be realized. Here we demonstrate such magnon valves based on van der Waals antiferromagnetic insulator MnPS3. By applying DC electric current through the gate electrode, we show that the second harmonic thermal magnon (SHM) signal can be tuned from positive to negative. The guaranteed zero crossing during this tuning demonstrates a complete blocking of SHM transmission, arising from the nonlinear gate dependence of the non-equilibrium magnon density in the 2D spin channel. Using the switchable magnon valves we demonstrate a magnon-based inverter. These results illustrate the potential of van der Waals anti-ferromagnets for studying highly tunable spin-wave physics and for application in magnon-base circuitry in future information technology.

Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids

“…In 2019, Xing et al (115) demonstrated long-distance magnon transport in a quasi-2D AF insulator MnPS3 via a nonlocal SSE. Subsequently, the nonlocal SSE in this system is shown to be turned on and off by an electrical current though a metal gate due to the nonlinear gate dependence (116). In 2020, Lee et al (163) showed that the insertion of a monolayer WSe2 between YIG and Pt layers enhances the LSSE voltage by a factor of ∼ 5 compared to that in an YIG/Pt system, showing a new avenue on SSE research with 2D transition dichalcogenide materials.…”

“…The ℓm estimation may be affected by the locally distributed ∇T , which is discussed in References (95,96). So far, nonlocal SSEs are reported in several magnets such as ferrimagnetic YIG (94,95,96,97,98,99,100,101,102,103,104,105), Gd3Fe5O12 (106), Tm3Fe5O12 (107), NiFe2O4 (108), MgAl0.5Fe1.5O4 (109), antiferromagnetic Cr2O3 (111,112), α-Fe2O3 (37,110), NiO (34), YFeO3 (113), BiFeO3 (114), and 2D layered magnets MnPS3 (115,116) and CrBr3 (117).…”

Spin Hall Magnetoresistance Effect from a Disordered Interface

“…The SMR effect has been observed in a system consisting of the van der Waals compound MoS 2 doped with Co impurities and Ta . However, experimental studies of the SMR effect in proper layered magnets are lacking so far, while a variety of studies on magneto-transport behavior in van der Waals magnetic compounds interfaced with HMs (Ta, Pt, and W) have been reported, highlighting the importance of such heterostructures for spintronic applications. − We note here that, till date, most of such interfaces are assembled by sputtering of a HM layer on top of the selected van der Waals material, even though their structural characterization is scarcely reported.…”

Exceptional spin wave dynamics in an antiferromagnetic honeycomb lattice

“…In the van der Waals antiferromagnetic(AFM) materials, the magnon transport over several micrometers has been experimentally observed [22], and the spin Nernst effect due to the nontrival topology of magnon band has been theoretically discussed [23,24]. Furthermore, the ability to tune spin wave by gate has been demonstrated in the AFM bilayer CI 3 [25] and the magnon valve structure made of MnPS 3 [26], while the topological magnon insulator has been realized in CrXTe 3 (X = Si, Ge) compounds [27].…”