Proposed mechanical method for switching the spin transport channel in two-dimensional magnetic metal-magnetic semiconductor van der Waals contacts

Chemically Controlled Reversible Magnetic Phase Transition in Two-Dimensional Organometallic Lattices

Developing an efficient method to reversibly control materials' spin order is urgently needed but challenging in spintronics. Though various physical field control methods have been advancing, the chemical control of spin is little exploited. Here, we propose a chemical means for such spin manipulation, i.e., utilizing the well-known lactim-lactam tautomerization to reversibly modulate the magnetic phase transition in two-dimensional (2D) organometallic lattices. The proposal is verified by theoretically designing several 2D organometallic frameworks with antiferromagnetic to ferrimagnetic spin order transformation modulated by lactim-lactam tautomerization on organic linkers. The transition originates from the change in spin states of organic linkers (from singlet to doublet) via tautomerization. Such a transition further switches materials' electronic structures from normal semiconductors with zero spin polarization to bipolar magnetic semiconductors with valence and conduction band edges 100% spin polarized in opposite spin channels. Moreover, the magnitude of magnetic anisotropy energy also enhances by 5- to 9-fold.

CrSbS3 monolayer: a potential phase transition ferromagnetic semiconductor

Two dimensional intrinsic ferromagnetic semiconductors with controllable magnetic phase transition are highly desirable for spintronics. Nevertheless, reports on their successful experimental realization are still rare. Herein, based on first principles calculations, we propose to achieve such a functional material, namely CrSbS₃ monolayer by exfoliating from its bulk crystal. Intrinsic CrSbS₃ monolayer is a ferromagnetic half semiconductor with a moderate bandgap of 1.90 eV. It features an intriguing magnetic phase transition from ferromagnetic to antiferromagnetic when applying a small compressive strain (∼2%), making it ideal for fabricating strain-controlled magnetic switches or memories. In addition, the predicted strong anisotropic absorption of visible light and small effective masses make the CrSbS₃ monolayer promising for optoelectronic applications.