Work

Metallic Electrooptic Effect in Twisted Double-Bilayer Graphene

Year: 2026

Type: article

Abstract: Recent theoretical advances have highlighted the role of Bloch state intrinsic properties in enabling unconventional electro-optic (EO) phenomena in bulk metals, offering novel strategies for dynamic optical control in quantum materials. Here, we identify an alternative EO mechanism in bulk metallic systems that arises from the interplay between Berry curvature and the orbital magnetic moment of Bloch electrons. Focusing on twisted double-bilayer graphene (TDBG), we show that the enhanced intrinsic properties of moiré Bloch bands give rise to a sizable linear magnetoelectric EO response, a first-order, electric-field-induced non-Hermitian correction to the gyrotropic magnetic susceptibility. This mechanism dominates in C 3 z -symmetric TDBG, where EO contributions originating from the Berry curvature dipole (BCD) are symmetry-forbidden. Our calculations reveal giant, gate-tunable linear and circular dichroism in the terahertz regime, establishing a robust and tunable platform for ultrafast EO modulation in two-dimensional materials beyond the BCD paradigm.

Source: Nano Letters

DOI: 10.1021/acs.nanolett.5c05662

Authors: D. J. P. de Sousa, N. Roldan-Levchenko, C. O. Ascencio, J. D. S. Forte, Paul M. Haney, Tony Low

Institutions: University of Minnesota, National Institute of Standards and Technology, Physical Measurement Laboratory

Language: English

Topic: Topological Materials and Phenomena

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Office of Naval Research