Large thermoelectric transport in magnetically coupled CrI₃/1T-MoS₂ vdW heterostructure via spin–charge interconversion

Abstract

Low-dimensional materials with prominent thermoelectric (TE) effect play a pivotal role in realizing state-of-the-art nanoscale TE devices. The fusion of TE effect with the magnetism through seamless integration of thermoelectric and magnetic materials in the 2D limit offers access to control longitudinal as well as transverse TE properties via magnetic proximity effect (MPE). Herein, we design a vdW heterostructure of metallic 1T-MoS2 with promising TE properties and a layer-dependent magnetic CrI3 material. The result highlights exotic electronic and magnetic configurations of the designed ML-CrI3/1T-MoS2 vdW heterostructure, which show magnetically-coupled TE characteristics. The observed remarkable magnetic proximity stems from large magnetic anisotropy energy and spin polarization, which are found to be 2.21 meV/Cr and 12.30%, respectively. To this end, the semiconducting CrI3 layer with intrinsic magnetism leads to efficient control and tunability of the observed spin-correlated anomalous Nernst effect (ANE). Moreover, a large dimensionless Figure of merit of ~ 6 and a power factor of ~ 3.8×10^11/τ_° Wm^(-1) K^(-2) s^(-1) near the Fermi level at 300K endorse the rejuvenated TE effect. The strong relativistic spin-orbit coupling validates the significant correlation of TE properties with intrinsic magnetic configuration. The present study underscores the significance of the magnetic proximity-governed TE effect in vdW heterostructures to engineer low-dimensional thermoelectric (TE) devices.


Twist Proximity-Endowed Large Figure of Merit in a Band-Modulated CrI3/1T-MoS2 Moiré Superlattice

“…However, these two angles still possess large enough values of figure of merit, which are estimated to be 1.32 and 1.08 (i.e., ZT > 1) at 200 K. The observed maximum value of ZT is comparatively larger than that of previously reported vdW heterostructures such as 2.8 (graphene/MoS 2 ) and 3.5 (MoS 2 /MoSe 2 ), etc. − Also, a graphene-based 2D TI nanoribbon hosts a maximum zT value of 3, which is lower than that of the observed zT in the designed moiré superlattices . Besides, the nontwisted (0°) bilayer exhibits a maximum zT value of ∼6 . Though the 0° bilayer presents a larger value of zT than moiré superlattices, this behavior is observed at the higher energy region away from the Fermi level due to its metallic nature.…”

“…The local effect of twist is clearly apparent, which prompts bandgap modulation along with a flat band in the system. The nontwisted (θ = 0°) vdW heterostructure consisting of ML CrI 3 and ML 1T-MoS 2 possesses metallic behavior . However, the incorporation of the twist effect leads to the bandgap opening at different high-symmetry points with varying magnitude at specific twist angles.…”