Valley and spin splittings in a valley-layer-locked monolayer via atomic adsorption

TL;DR

This paper demonstrates how atomic adsorption on a TiSiCO monolayer can lift valley and spin degeneracies, enabling tunable spin-valley-layer interactions for advanced optoelectronic applications.

Contribution

It introduces a novel method of inducing and tuning valley and spin splittings in a monolayer via atomic adsorption and external electric fields.

Findings

Valley and spin degeneracies are lifted in TiSiCO monolayer.

Atomic adsorption creates effective electric and magnetic fields.

Tunable spin and valley splittings enable selective exciton creation.

Abstract

To date, a number of valley materials have been discovered with the spin-valley or valley-layer couplings. It is highly desirable to realize the interplay of more electronic degrees of freedom in a valley material. Based on the first-principles calculations, we demonstrate the valley and spin degeneracy liftings in the band structure of a TiSiCO monolayer, with the help of the selective expression of the layer pseudospin via atomic adsorption. The introduction of the transition-metal adatoms provides an effective electric field and magnetic proximity effect, giving rise to the valley and spin splittings. These splittings can be further tuned by applying an external electric field. According to the modified band structure, various interlayer excitons with different combinations of spins and electric dipoles are selectively created, under the optical field of appropriate frequencies. The tunable spin and valley splittings in atom adsorbed TiSiCO monolayer offer opportunities for exploring the interactions between spin, valley and layer pseudospin, and designing advanced optoelectronic devices.