Habib Rostami: Dynamical strain and phonon engineering in 2D materials
Abstract
Static and dynamic deformation provide powerful tools to control and modulate electronic properties in crystalline quantum materials. Two-dimensional (2D) materials with layered structures show remarkable elastic properties and are a promising platform for flexible electronic and optoelectronic technologies. Electron dynamics in deformed 2D materials can be described by quantum field theory approaches in curved space and effective lattice models. Intriguingly, chiral electrons and other collective excitations experience lattice deformations as a synthetic gauge potential leading to robust physical consequences such as flat-band formation, quantum Hall effect, or geometric Meissner effect. In this talk, I will review strain engineering in conventional semiconductors and revisit novel strain physics in 2D materials, such as graphene and transition metal dichalcogenides, on a broad scope by underlining the implication of the pseudo-gauge field, piezoelectricity, elastooptic, and acoustoelectric. Compared to recent experimental measurements in graphene, I will present the acoustogalvanic effect [1,2] as a rectification process of acoustic waves in materials hosting Dirac quasiparticles with linear dispersion. As another example, I will report strain-induced chiral phonon modes [3] with non-trivial topology and angular momentum in 2D materials. Finally, if time allows, I will explain a mechanism for the light-induced out-of-phase displacement of atomic layers in 2D materials that can be employed to control the layer stacking order coherently [4].
[1] P.O. Sukhachov, H. Rostami, Phys. Rev. Lett. 124, 126602 (2020)
[2] P. Bhalla, G. Vignale, and H. Rostami, Phys. Rev. B 105, 125407 (2022)
[3] H. Rostami, F Guinea, E Cappelluti, Phys. Rev. B 105, 195431 (2022)
[4] H. Rostami, Phys. Rev. B 106, 155405 (2022)
Det går både att delta i seminariet på plats eller via Zoom.
Plats: PJ-salen, Institutionen för fysik, Kemigården 1, Göteborg
Zoom-länk: https://gu-se.zoom.us/j/64681043702
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