Dirac Fermion in Strongly-Bound Graphene Systems

TL;DR

This paper demonstrates that strongly-bound graphene systems with transition metal intercalation, such as Mn on SiC, can host a Dirac cone similar to free-standing graphene, maintaining key electronic properties while enhancing stability.

Contribution

It introduces a new class of stable, strongly-bound graphene systems with Dirac cones formed through hybridization with transition metals, supported by first-principles calculations.

Findings

Dirac cone preserved in strongly-bound graphene/transition metal systems

Transport behavior similar to free-standing graphene up to 0.6 V bias

Fermi velocity reduced to half of that in free-standing graphene

Abstract

It is highly desirable to integrate graphene into existing semiconductor technology, where the combined system is thermodynamically stable yet maintain a Dirac cone at the Fermi level. Firstprinciples calculations reveal that a certain transition metal (TM) intercalated graphene/SiC(0001), such as the strongly-bound graphene/intercalated-Mn/SiC, could be such a system. Different from free-standing graphene, the hybridization between graphene and Mn/SiC leads to the formation of a dispersive Dirac cone of primarily TM d characters. The corresponding Dirac spectrum is still isotropic, and the transport behavior is nearly identical to that of free-standing graphene for a bias as large as 0.6 V, except that the Fermi velocity is half that of graphene. A simple model Hamiltonian is developed to qualitatively account for the physics of the transfer of the Dirac cone from a dispersive system (e.g., graphene) to an originally non-dispersive system (e.g., TM).