Nanoscale view of engineered massive Dirac quasiparticles in lithographic superstructures

Abstract

Massive Dirac fermions are low-energy electronic excitations characterized by a hyperbolic band dispersion. They play a central role in several emerging physical phenomena such as topological phase transitions, anomalous Hall effects and superconductivity. This work demonstrates that massive Dirac fermions can be controllably induced by lithographically patterning superstructures of nanoscale holes in a graphene device. Their band dispersion is systematically visualized using angle-resolved photoemission spectroscopy with nanoscale spatial resolution. A linear scaling of effective mass with feature sizes is discovered, underlining the Dirac nature of the superstructures. In situ electrostatic doping dramatically enhances the effective hole mass and leads to the direct observation of an electronic band gap that results in a peak-to-peak band separation of (0.64 $\pm$ 0.03) eV, which is shown via first-principles calculations to be strongly renormalized by carrier-induced screening. The presented methodology outlines a new approach for band structure engineering guided by directly viewing structurally- and electrically-tunable massive Dirac quasiparticles in lithographic superstructures at the nanoscale.

37 pages, 12 figures (includes supporting information). A revised version has been published in ACS Nano

References in corpus (11)

• Energy Band Gap Engineering of Graphene Nanoribbons
• Chaotic Dirac billiard in graphene quantum dots
• Graphene Antidot Lattices - Designed Defects and Spin Qubits
• Energy gaps in etched graphene nanoribbons
• Wedging Transfer of Nanostructures
• Electronic properties of graphene antidot lattices
• Weak Localization and Transport Gap in Graphene Antidot Lattices
• Renormalization of quasiparticle band gap in doped two-dimensional materials from many-body calculations
• Super-Resolution Nanolithography of Two-Dimensional Materials by Anisotropic Etching
• Electronic transport in disordered graphene antidot lattice devices
• Electronic and optical properties of graphene antidot lattices: Comparison of Dirac and tight-binding models

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