Ultrafast valley polarization of graphene nanorings

Here, we study theoretically electron dynamics of a graphene nanoring placed in the field of an ultrashort optical pulse. We describe the graphene nanoring within an effective model with infinite mass boundary conditions. For an optical pulse with a duration of just a few femtoseconds, the electron...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B 2022-10, Vol.106 (15), Article 155147
Main Authors: Zafar, Ahmal Jawad, Mitra, Aranyo, Apalkov, Vadym
Format: Article
Language:English
Subjects:
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Materials Science
Physics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Here, we study theoretically electron dynamics of a graphene nanoring placed in the field of an ultrashort optical pulse. We describe the graphene nanoring within an effective model with infinite mass boundary conditions. For an optical pulse with a duration of just a few femtoseconds, the electron dynamics is coherent and is described by a time-dependent Schrödinger equation. If the optical pulse is circularly polarized, then two valleys of graphene are populated differently, resulting in a finite valley polarization of the system after the pulse. Such a valley polarization is a unique property of graphene nanoscale systems, while for a graphene monolayer, a circularly polarized pulse does not produce any valley polarization. The valley polarization of the graphene nanoring depends on parameters of the system, such as inner and outer radii. With the system's size increasing, the valley polarization monotonically decreases, converging to its zero value for the infinite graphene monolayer.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.106.155147