posted on 2023-05-26, 12:35authored byYangyang Feng, Ying Dai, Baibiao Huang, Liangzhi Kou, Yandong Ma
The layer Hall effect (LHE) is of fundamental and practical
importance
in condensed-matter physics and material science; however, it was
rarely observed and usually based on the paradigms of persistent electric
field and sliding ferroelectricity. Here, a new mechanism of LHE is
proposed by coupling layer physics with multiferroics using symmetry
analysis and a low-energy k·p model.
Due to time-reversal symmetry breaking and valley physics, the Bloch
electrons on one valley will be subject to a large Berry curvature.
This combined with inversion symmetry breaking gives rise to layer-polarized
Berry curvature and can force the electrons to deflect in one direction
of a given layer, thereby generating the LHE. We demonstrate that
the resulting LHE is ferroelectrically controllable and reversible.
Using first-principles calculations, this mechanism and predicted
phenomena are verified in the multiferroic material of bilayer Co2CF2. Our finding opens a new direction for LHE
and 2D materials research.