Electrostatic confinement of electrons in an integrable graphene quantum dot

Abstract

We compare the conductance of an undoped graphene sheet with a small region subject to an electrostatic gate potential for the cases that the dynamics in the gated region is regular (disc-shaped region) and classically chaotic (stadium). For the disc, we find sharp resonances that narrow upon reducing the area fraction of the gated region. We relate this observation to the existence of confined electronic states. For the stadium, the conductance looses its dependence on the gate voltage upon reducing the area fraction of the gated region, which signals the lack of confinement of Dirac quasiparticles in a gated region with chaotic classical electron dynamics.

4 pages, 4 figures; [v2] Added discussion of large aspect ratios

References in corpus (13)

• Chiral tunneling and the Klein paradox in graphene
• Chaotic Dirac billiard in graphene quantum dots
• Andreev reflection and Klein tunneling in graphene
• Time Reversal Polarization and a Z_2 Adiabatic Spin Pump
• Quantum-limited shot noise in graphene
• Selective transmission of Dirac electrons and ballistic magnetoresistance of \textit{n-p} junctions in graphene
• Aharonov-Bohm effect and broken valley-degeneracy in graphene rings
• Topological delocalization of two-dimensional massless Dirac fermions
• Quasi-bound states of quantum dots in single and bilayer graphene
• Graphene quantum dots: Beyond a Dirac billiard
• Symmetry Classes in Graphene Quantum Dots: Universal Spectral Statistics, Weak Localization, and Conductance Fluctuations
• Z2 topological term, the global anomaly, and the two-dimensional symplectic symmetry class of Anderson localization
• Impurity-assisted tunneling in graphene