Dirac antidot superlattices for electrons in III-V semiconductors
Super-réseau d’anti-points de Dirac pour les électrons dans les semiconducteurs III-V
The project aims at studying electrons confined in quasi two-dimensional (2D) artificial honeycomb lattices which are specifically designed to generate complex band structures, including Dirac cones and non-trivial flat bands. The superlattices, which can be seen as artificial graphene materials, will be obtained by turning conventional III-V semiconductor heterostructures into triangular antidot lattices at the limit of quantum confinement. Guided by predictive atomistic tight-binding calculations, periodic potential modulations will be induced in epitaxially-grown InGaAs/InP or InGaAs/AlInAs heterostructures by either lateral metallic gates or inclusions of barrier materials. The patterns will be defined by high resolution e-beam or block copolymer lithographies pushed to their limit in order to reach lattice parameters (periodicity) between 45 and 10 nm, allowing to obtain Dirac cones covering energy ranges up to tens of meV. Motivated by the interest in finding new types of quantum states which can be manipulated in tunable solid-state devices, state-of-the-art low-temperature transport measurements and local-probe spectroscopy will be employed to reveal Dirac fermions and non-trivial band structures predicted in these artificial 2D materials. Magneto-transport experiments will be used to investigate the complex evolution of the energy bands when magnetic and lattice scales are comparable.
Institut Néel (Julien Renard, Vincent Bouchiat)
LCPO (Guillaume Fleury, Karim Aissou)
IEMN (Xavier Wallart, Ludovic Desplanque, Christophe Coinon, François Vaurette, Dmitri Yarekha, Bruno Grandidier, Didier Stiévenard, Maxime Berthe, Athmane Tadjine, Nathali Franchina, Yannick Lambert, Christophe Delerue)
Debye Institute (group of Daniël Vanmaekelbergh)
Christophe Delerue: email@example.com
This project is supported by the French National Research Agency (ANR) project “Dirac-III-V” ANR-16-CE24-0007-01 (from October 16 to September 2021).
From lattice Hamiltonians to tunable band structures by lithographic design, Athmane Tadjine, Guy Allan, and Christophe Delerue, Phys. Rev. B 94, 075441 (2016).
Topological protection of electronic states against disorder probed by their magnetic moment, Athmane Tadjine and Christophe Delerue, Phys. Rev. B 95, 235426 (2017).
Figure: example of band structure calculated for a honeycomb lattice patterned in a semiconductor layer. There are two Dirac points at K, at two energies (~2 and ~12 meV), where two bands are in contact and have a linear dispersion with the wavevector k.