Layer Hall Effect in Multiferroic Two-Dimensional Materials

• Published in: Nano letters Vol. 23; no. 11; pp. 5367 - 5372
• Main Authors: Feng, Yangyang, Dai, Ying, Huang, Baibiao, Kou, Liangzhi, Ma, Yandong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.06.2023
• Subjects: ferroelectric; multiferroic; first-principles; two-dimensional materials; layer Hall effect
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/acs.nanolett.3c01651

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.