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Bulk Magnetization of graphene. Tight binding approximation : the mobile electrons are always located in the proximity of an atom , and then are conveniently described by the p z atomic orbital of the atoms it touches. : normalized wavefunction for an isolated atom.
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Bulk Magnetization of graphene Tight bindingapproximation: the mobile electrons are alwayslocated in the proximity of an atom, and then are convenientlydescribed by the pzatomicorbital of the atomsittouches. : normalized wavefunction for an isolatedatom. 1 conduction electron for each C atom in the state. Unit cell (WXYZ) contains 2 atoms ( and ). (foundamental lattice displacement). The base functions are periodicalfunctions with the sameperiodicityas the (2D) lattice. kis a wavevector. Itdefines a reciprocal lattice and actsas a kind of quantum number. Extended wavefunction A. Barbon, Corso di Magnetochimica. A.A. 2013-14. Graphene
The band theory of graphene Variationalprincipleto obtain the best value of substituting the wavefunction in the Schroedingerequation: By pre-multiplicationby or and integrationwehave: Number of unitcells We obtain: /N A. Barbon, Corso di Magnetochimica. A.A. 2013-14. Graphene
: interactionbetween an or atom with itself : interactionbetween first neighbors of the sametype ( or ) : interaction between first neighbors of opposite type ( and ) Energy levelsasfunction of ky (kx=0) Zero band-gap Calculation of the density of states: A. Barbon, Corso di Magnetochimica. A.A. 2013-14. Graphene
N° of free electrons plus positive holes per atom: : Fermi distribution At room temperature () the effectivenumber of free electrons (), per atom, is Itispossible to show that the number of electronicenergystates per atom: : number of atoms in the lattice N(E) E Ec A. Barbon, Corso di Magnetochimica. A.A. 2013-14. Graphene
Magnetic susceptivity: G. Wagoner, Phys. Rev., 118, 647 (1960). A. Barbon, Corso di Magnetochimica. A.A. 2013-14. Graphene