College Papers

Calculations Car-Parrinello molecular dynamics have been used to

Calculations have been performed
in the framework of Spin Density Functional Theory as implemented in quantum
espresso package using the
generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE)
exchange-correlation functional. Plane wave
cutoff is 45 RY, ultrasoft pseudopotentials have been used throughout the
study. Brillouin zone has been integrated with Gaussian smearing of 0.04Ry. Convergence
energy is 0.005 Ry for a 10*10*10 Monkhorst–Pack K point grid. The local magnetic moment (that is, net spin polarization on an
atom) was obtained by integrating the local density of states up to the Fermi
level for spin-up and spin-down states separately and then taking the
difference between the two.

Car-Parrinello molecular dynamics have
been used to the difference in the total
energy (etot) between relaxed and randomized positions can be used to estimate
the temperature that will be reached by the system. Usibng nose thermostat
temperature chanves have been done.

kinetic
energy cutoff 450 eV Full relaxation of magnetization was performed for
spin-polarized calculations. we used all-electron broken symmetry DFT with an
atom-centered basis 6-311G**1 and hybrid exchange-correlation
functionals B3LYP1 Ref. 481 and PBE0 Ref. 491 to verify the energetics
and existence of the magnetic phases. The main reason for these calculations
was to check if there were any strong electron correlation effects by adding
exact exchange to help reduce the self-interaction error1

the
finite-temperature magnetic properties of Co we performed standard Monte Carlo
calculations of a Heisenberg Hamiltonian with fixed-size magnetic moments by
means of the Metropolis algorithm36. We applied the magnetic force theorem44
and the Liechtenstein-Katsnelson-Antropov-Gubanov (LKAG) formalism45, 46 as
implemented in the self-consistent field multiple-scattering
Korringa-Kohn-Rostoker (KKR) Green’s function approach47, 48 to calculate the
exchange coupling constants.

A
periodic saw-toothtype potential perpendicular to the direction of the ribbon
edge is used to simulate the external electric fields (Eext) in a supercell