Persistent currents in Dirac fermion rings

Doru Sticlet (1, 2) , Balázs Dóra (3, 4) , Jérôme Cayssol (1, 2)

1 LOMA - Laboratoire Ondes et Matière d'Aquitaine
2 MPI-PKS - Max-Planck-Institut für Physik komplexer Systeme
3 Department of Physics [Budapest]
4 BME-MTA Exotic Quantum Phases Research Group

The persistent current in strictly one-dimensional Dirac systems is investigated within two different models, defined in the continuum and on a lattice, respectively. The object of the study is the effect of a single magnetic or nonmagnetic impurity in the two systems. In the continuum Dirac model, an analytical expression for the persistent current flowing along a ring with a single delta-like magnetic impurity is obtained after regularization of the unbounded negative energy states. The predicted decay of the persistent agrees with the lattice simulations. The results are generalized to finite temperatures. To realize a single Dirac massless fermion, the lattice model breaks the time-reversal symmetry, and, in contrast with the continuum model, a pointlike nonmagnetic impurity can lead to a decay in the persistent current.

Mots clés: Persistent currents; Electron states and collective excitations in multilayers; Electronic transport in nanoscale materials and structures; quantum wells; mesoscopic and nanoscale systems

Domaines: Matière Condensée [cond-mat]

Doru Sticlet, Balázs Dóra, Jérôme Cayssol. Persistent currents in Dirac fermion rings. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 88 (20), pp.205401. ⟨10.1103/PhysRevB.88.205401⟩. ⟨hal-00910687⟩