Impurity cyclotron resonance of anomalous Dirac electrons in graphene

Abstract

We have investigated a new feature of impurity cyclotron resonances common to various localized potentials of graphene. A localized potential can interact with a magnetic field in an unexpected way in graphene. It can lead to formation of anomalous boundstates that have a sharp peak with a width R in the probability density inside the potential and a broad peak of size magnetic length ℓ outside the potential. We investigate optical matrix elements of anomalous states and find that they are unusually small and depend sensitively on the magnetic field. The effect of many-body interactions on their optical conductivity is investigated using a self-consistent time-dependent Hartree-Fock approach. For a completely filled Landau level we find that an excited electron-hole pair, originating from the optical transition between two anomalous impurity states, is nearly uncorrelated with other electron-hole pairs, although it displays substantial exchange self-energy effects. This absence of correlation is a consequence of a small vertex correction in comparison to the difference between renormalized transition energies computed within the one electron-hole pair approximation. However, an excited electron-hole pair originating from the optical transition between a normal and an anomalous impurity state can be substantially correlated with other electron-hole states with a significant optical strength.

Stability of Anomalous States of a Local Potential in Graphene

“…These anomalous results provide a new magnetospectroscopic feature in impurity cyclotron resonances of graphene. 11 Our results may provide a systematic guide in choosing the optimal values for which the anomalous states may be observed optically. It would be interesting to observe the magnetospectroscopic features of anomalous states.…”

“…The optical transitions originating from these states are depicted in Figure 3. Kim, Yang, and MacDonald 11 have proposed that these anomalous states can provide a new magnetospectroscopic feature in impurity cyclotron resonances 12 13 of graphene.…”

“…J x 0 J 2 are given11 inTable I forvaries values of V I /E M R/ . The optical transitions involving the anomalous states are denoted by J J = 1/2 −1/2 and −1/2 −3/2 .…”

Interaction-induced conductance from zero modes in a clean magnetic graphene waveguide

“…When the n = 0 level is partially filled, with all negative-energy states occupied, the noninteracting conductance of the MGW vanishes identically since all n = 0 current matrix elements are zero. We here demonstrate that, nonetheless, a finite conductance emerges due to inter-band Coulomb interactions (corresponding to Landau level mixing for d = 0 [44]). The transport features related to the zero-energy band differ qualitatively from those of finite-energy bands, and thus should be easy to identify experimentally.…”

Microwave-dressed electron–impurity interaction in a two-dimensional electron gas system under intense microwave radiation fields and weak magnetic fields

“…Such scattering events at low temperature can lead to electronic resonant transitions between different LLs, more specially, the effects of impurity CR (ICR) can be observed experimentally [12][13][14][15]. These effects of ICR in various electronic systems are already extensively investigated theoretically in the linea (in radiation field) approximation [16][17][18][19][20]. More interesting, when the radiation field is strong enough, apart from single-photon processes, multiphoton processes (nonlinear ICR) are possible.…”