Roles of edge states in the specific heat and magnetic ordering of graphene strips

✍ Scribed by K.-S. Yi; D. Kim; K.-S. Park; J.J. Quinn

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 377 KB
• Volume: 40
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2007.10.064

✦ Synopsis

The role of edge states in the electronic specific heat and magnetic ordering of graphene strip is investigated by diagonalizing a lattice Hamiltonian for graphene strips. The magnetization of the edge sites is evaluated by employing the on-site Coulomb repulsion U within a mean-field approximation. We find that edge states give extra strong enhancement in the specific heat of zigzag strips at very low temperatures in addition to the C el ' gT a behavior of two-dimensional (2D) massless fermions in graphene with g % 7:18 k B and a % 2:27 at low temperatures. The onset value U c for ferrimagnetic ordering in zigzag strips depends notably on the next nearest neighbour (NNN) hopping strength t 2 but not much on the Rashba spin-orbit coupling V R for a given t 2 .