Strain-Controllable Phase and Magnetism Transitions in Re-Doped MoTe₂ Monolayer

Abstract

Developing approaches to effectively manipulate the magnetic states and phase transition is critical to the application of transition metal dichalcogenides (TMDs) in spintronic or phaseswitching devices. In this work, Re doping and strain engineering are combined to control the phase transition between 2H-and 1T′-MoTe 2 and to induce magnetism in the system based on density functional theory calculations. The structural transformation from 2H-to 1T′phase is predicted to occur around a doping concentration of 11%. The intrinsically nonmagnetic 2H-MoTe 2 structures with various doping concentrations become magnetic under a biaxial tensile strain, and the magnetic moment slowly increases with strain. For 1T′-MoTe 2 , only monolayers with a doping concentration of less than 10% exhibit magnetism under relatively high strain. The conversion from ionic to covalent bonding and the self-exchange mechanisms are found to be the origin of the tunable magnetic behaviors under strain. The synchronous emergence of the structural transition and magnetism in Re-doped MoTe 2 under isotropic strain offers a great possibility to design novel and tunable spintronic devices.

Tuning the physical properties of ultrathin transition-metal dichalcogenides via strain engineering

“…Application of tensile strain can lead to magnetism in TM-atom-doped TMDs lms, even magnetic transformation in TM atoms substituted TMDs, which can be attributed to the conversion from covalent to ionic bonding between TM atoms and chalcogens atoms. 104,105 For instance, by application of tensile strain of 8%, a strain-induced phase transition from 2H phase to 1T phase can be obtained in the relatively low Re doping concentration in monolayer MoTe 2 , accompanied by a sudden magnetization phenomenon ( Fig. 6a-d).…”

Strain engineering of two‐dimensional materials: Methods, properties, and applications

“…By applying a certain magnitude and direction of in‐plane strain, the ferromagnetic phase of CrI 3 can be transformed into either the Néel antiferromagnetic or ferrimagnetic phase 127 . In addition, similar synchronous phase transition induced by strain can also be observed in Re‐doped MoTe 2 materials 128 . Ma et al found that the structural phase transition from 2H to 1T′ occurred under the Re‐doped concentration of ∼11%, and nonmagnetic Mo 1 − x Re x Te 2 monolayer transformed into the ferromagnetism state simultaneously under biaxial strain.…”

Strain-Induced Modulation of Spin Configuration in LaCoO3

“…For strained LaCoO 3 with intermediate-and high-spin configurations, the magnetic moment of Co increases with strain. This positive correlation between magnetic moment and strain is a general behavior, which was observed in various materials (Kushima et al, 2010;Hsu et al, 2018;Zhao et al, 2020b). Given the slight variation in the magnetic moment over each terrace, we take the average values over the corresponding strain range as the DFT calculated Mag Co , listed in Table 1.…”