QUANTUM-CONTROLLED VALLEYTRONIC DEVICES IN BILAYER GRAPHENE
Abstract
Quantum-Controlled Valleytronic Devices in Bilayer Graphene Hexagonal two-dimensional crystals, such as graphene and transition metal dichalcogenides, exhibit a pair of degenerate bands at the K and K’ valleys in momentum space. The valley electrons are characterized by non-trivial Berry curvatures, which give rise to anomalous quantum Hall states in monolayer graphene. Bilayer graphene(BLG) provides an attractive platform to explore topological valley physics: a tunable semiconductor bandgap can be induced in BLG using a vertical electrical field. Such gapped BLG features quantum valley-Hall effects, the valley counterpart of the quantum spin-Hall effects. Recently we demonstrated that a topologically protected onedimensional (1D) conducting channels at the AB-BA domain walls of gapped bilayer graphene. It was predicted that the 1D conducting channels arise from counter propagating chiral electrons with opposite valley. Such valley-polarized 1D chiral electron channels provide exciting opportunities for exploring topological phenomena in graphene and for valleytronic applications. Here we propose to investigate systematically of the quantum valley-Hall boundary states in bilayer graphene by combining advanced near-field optical spectroscopy and lowtemperature electrical transport measurements. Specifically, we will (1) determine realspace atomic structure of the AB-BA domain walls in exfoliated bilayer graphene, (2) obtain electronic structure and optical transitions at the AB-BA domain walls, and (3) establish the fundamental limit on the ballistic transport length of the 1D conducting channel. Based on such fundamental understanding of valley-polarized 1D channels, we will explore novel valleytronic devices including valley filters and valley valves based on bilayer graphene.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512651
Entities
People
- Feng Wang
Organizations
- Office of Naval Research
- United States Navy
- University of California Regents