Single-valley state in a two-dimensional antiferromagnetic lattice

We propose the concept of single-valley state in two-dimensional antiferromagnetic lattice, which intrinsically holds only one valley and thus robust valley-polarized physics. Using tight-binding model analysis, the physical mechanism to form the single-valley state is illustrated, and large magnetic moment and strong spin-orbit coupling are unveiled to define it. Furthermore, based on first-principles calculations, the single-valley state is predicted in a real material of single-layer BiFeO3. The spontaneous valley polarization in single-layer BiFeO3 is particularly huge, at least one order of magnitude higher than those of all the existing ferrovalley systems. Our work enriches the physics of two-dimensional valleytronics and provides a promising avenue to observe strong valley-polarized phenomena.

Automated summary

The study introduces the concept of a single-valley state in a two-dimensional antiferromagnetic lattice, predicting its existence in single-layer BiFeO3 through tight-binding model analysis and first-principles calculations. This enriches the physics of two-dimensional valleytronics and offers a promising avenue to observe strong valley-polarized phenomena.