Kim, Seungchul Ihm, Jisoon Choi, Hyoung Joon Son, Young-Woo 2024-01-20T11:02:43Z 2024-01-20T11:02:43Z 2021-08-31 2013-12 0038-1098 https://pubs.kist.re.kr/handle/201004/127416 We present a minimal but crucial microscopic theory for epitaxial graphene and graphene nanoribbons on the 4H-SiC(0001) surface - prototypical materials to explore physical properties of graphene in a large scale. Coarse-grained model Hamiltonians are constructed based on the atomic and electronic structures of the systems from first-principles calculations. From the theory, we unambiguously uncover origins of several intriguing experimental observations such as broken-symmetry states around the Dirac points and new energy bands arising throughout the Brillouin zone, thereby establishing the role of substrates in modifying electronic properties of graphene. We also predict that armchair graphene nanoribbons on the surface have a single energy gap of 0.2 eV when their widths are over 15 nm, in sharp contrast to their usual family behavior. (C) 2013 Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD ENERGY BANDGAP PHOTOEMISSION ORIGIN GAS Minimal single-particle Hamiltonian for charge carriers in epitaxial graphene on 4H-SiC(0001): Broken-symmetry states at Dirac points Article 10.1016/j.ssc.2013.09.034 1 SOLID STATE COMMUNICATIONS, v.175, pp.83 - 89 SOLID STATE COMMUNICATIONS 175 83 89 scie scopus 000329538200011 2-s2.0-84890041481 Physics, Condensed Matter Physics Article ENERGY BANDGAP PHOTOEMISSION ORIGIN GAS Epitaxial graphene Graphene nanoribbon Angle resolved photoemission Effective model