Dirac Materials

Discoveries of superfluid phases in 3He, high Tc superconductors, graphene and topological insulators have brought into focus materials where quasiparticles are described by same Dirac equation that governs behaviour of relativistic particles. This class of materials – Dirac materials – exhibits unusual universal features seen in numerous realizations: Klein tunnelling, chiral symmetries and impurity resonances. We have explored these similarities and discuss the unique role of symmetries that protect the Dirac spectrum. We investigated the symmetries of Dirac materials, quantum imaging, and means to control their properties. We have also used modern tools to design artificial Dirac Materials. For example one can design Bosonic Dirac materials that host bosonic Dirac excitations, something that would not be possible in particle physics.

Research falls into several areas:

Pumped Dirac Materials: Recent pump-probe experiments demonstrate the possibility that Dirac materials may be driven into transient excited states describable by two chemical potentials, one for the electrons and one for the holes. Given the Dirac nature of the spectrum, such an inverted population allows the optical tunability of the density of states of the electrons and holes, effectively offering control of the strength of the Coulomb interaction.

Transport properties:

Topological Aspects:

Review article
“Dirac Materials”
T.O. Wehling, A.M. Black-Schaffer, A.V. Balatsky
Advances in Physics, Vol. 63, Iss. 1 (2014)

We proposed to use the sensitivity of nodes in the electron spectrum of Dirac materials to induce controlled modifications of the Dirac points/lines via band structure engineering in artificial structures and via inelastic scattering processes with controlled doping. Results will expand our theoretical understanding and guide design of materials and engineered geometries that allow tunable energy profiles of Dirac carriers.

We have further developed the ideas of Dirac Materials and nontrivial properties they exhibit. We have primarily focused on local properties and transport.