Prof. dr Dietmar Ebert, Uniwersytet Humboldta w Berlinie

Effective Quantum Field Theory and Graphene

This is a pedagogical introduction into an "Effective QFT" - description of graphene. The lecture explains the "pseudospin" (sublattice) and "valley" (Dirac point) degrees of freedom of electrons of the graphene lattice. Then, using a tight-⁠⁠binding model, the effective Dirac Hamiltonian of quasirelativistic massless electrons is derived. On this basis, the so-⁠⁠called Klein paradox and the chiral symmetry breaking of the U(2) valley-⁠⁠sublattice symmetry are discussed. Finally, a pseudopotential model for defects in graphene is presented and its relation to defect-⁠⁠induced gauge fields is discussed.