Antiferromagnetism of the Hubbard Model on a Layered Honeycomb Lattice - Is MgB$_2$ a Nearly-Antiferromagnetic Metal?

Preprint
Publisher Website
Google Scholar
  • 8 March 2001
Abstract
Half-filled Hubbard model on a layered honeycomb lattice is studied as a model for boron 2pz bands of MgB2. Monte Carlo method as well as random phase approximation method are used for investigation of antiferromagnetism at the ground state. On a single-layer honeycomb lattice, paramagnetic to antiferromagnetic phase transition occurs at a finite value of the repulsion strength Uc/t = 3.6, due to the loss of the density of states at the fermi level. On a layered honeycomb lattice, inter-layer hopping term creates the perfect nesting of the fermi surface, and causes the antiferromagnetism to occur at Uc=0. We discuss that MgB2 might possibly be a nearly-antiferromagnetic metal, where antiferromagnetism of 2pz bands is destroyed by carrier doping.

This publication has 0 references indexed in Scilit: