Please use this identifier to cite or link to this item: https://doi.org/10.1103/PhysRevA.80.043411
Title: Ultracold fermions in a graphene-type optical lattice
Authors: Lee, K.L.
Grémaud, B. 
Han, R.
Englert, B.-G. 
Miniatura, C. 
Issue Date: 19-Oct-2009
Citation: Lee, K.L., Grémaud, B., Han, R., Englert, B.-G., Miniatura, C. (2009-10-19). Ultracold fermions in a graphene-type optical lattice. Physical Review A - Atomic, Molecular, and Optical Physics 80 (4) : -. ScholarBank@NUS Repository. https://doi.org/10.1103/PhysRevA.80.043411
Abstract: Some important features of the graphene physics can be reproduced by loading ultracold fermionic atoms in a two-dimensional optical lattice with honeycomb symmetry and we address here its experimental feasibility. We analyze in great detail the optical lattice generated by the coherent superposition of three coplanar running laser waves with respective angles 2π/3. The corresponding band structure displays Dirac cones located at the corners of the Brillouin zone and close to half-filling this system is well described by massless Dirac fermions. We characterize their properties by accurately deriving the nearest-neighbor hopping parameter t0 as a function of the optical lattice parameters. Our semiclassical instanton method proves in excellent agreement with an exact numerical diagonalization of the full Hamilton operator in the tight-binding regime. We conclude that the temperature range needed to access the Dirac fermions regime is within experimental reach. We also analyze imperfections in the laser configuration as they lead to optical lattice distortions which affect the Dirac fermions. We show that the Dirac cones do survive up to some critical intensity or angle mismatches which are easily controlled in actual experiments. In the tight-binding regime, we predict, and numerically confirm, that these critical mismatches are inversely proportional to the square root of the optical potential strength. We also briefly discuss the interesting possibility of fine tuning the mass of the Dirac fermions by controlling the laser phase in an optical lattice generated by the incoherent superposition of three coplanar independent standing waves with respective angles 2π/3. © 2009 The American Physical Society.
Source Title: Physical Review A - Atomic, Molecular, and Optical Physics
URI: http://scholarbank.nus.edu.sg/handle/10635/112539
ISSN: 10502947
DOI: 10.1103/PhysRevA.80.043411
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

101
checked on Oct 15, 2018

WEB OF SCIENCETM
Citations

97
checked on Nov 15, 2017

Page view(s)

36
checked on Oct 5, 2018

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.