2026/05/11(Mon) 11:00 -12:00 五樓第一會議室 5F, 1st Meeting Room
Title
Graphene nanoslide and frustrated magnetism in strained graphene
Speaker
Dr. Christophe De Beule (Department of Physics, NCKU)Abstract
Lattice deformations in graphene couple to the low-energy Dirac electrons as effective scalar and gauge fields. In
this talk, I will discuss how strain-induced pseudogauge fields can be leveraged to design straintronics devices for
studying quantum interference and strongly-correlated electronic phases.
First, I will introduce pseudogauge fields in graphene, and discuss the role of acoustic and optical deformations
[1]. I will then present a theory for a simple straintronics device that consists of graphene suspended between two
misaligned gate electrodes, resulting in a pseudogauge barrier from localized uniaxial strain. This device hosts
gate-tunable conductance resonances, a 1D channel of valley chiral or counterpropagating modes that provides a
simple platform for Luttinger liquid physics, and sublattice Friedel oscillations. Moreover, our results also apply to
the surface of a topological insulator where the role of strain is replaced by a magnetic barrier. Finally, I will show
that our theory explains a recent experiment in terms of a hybrid pseudogauge and electrostatic interferometer [2].
In the second part, I will show how topological flatbands can be engineered in bilayer graphene with periodic strain
by depositing graphene on a patterned hBN substrate [3]. I will share experimental results that show evidence of
frustrated magnetism in this system, discuss the microscopic origin of the local spins, and show that classical
Monte Carlo spin-ice simulations can explain the observed hysteresis in terms of emergent magnetic charges.
[1] Elastic Screening of Pseudogauge Fields in Graphene, C. De Beule, R. Smeyers, W. N. Luna, E. J. Mele, and
L. Covaci, Phys. Rev. Lett. 134, 046404 (2025).
[2] Gate-Tunable Resonances and 1D Channel in a Graphene Nanoslide, C. De Beule, M.-H. Liu, B. Partoens,
and L. Covaci, Phys. Rev. B Letter, In Press (arXiv:2512.22982) (2025).
[3] Frustrated Magnetism in Strain-Patterned Graphene Superlattices, Y.-C. Hsieh, W.-H. Kao, C. De Beule, et al.
Under review in Nature (2025).
Language
演講語言 (Language): in English