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A monolayer of a transition metal dichalcogenide such as WSe2 is a two-dimensional direct-bandgap valley-semiconductor(1,2) having an effective honeycomb lattice structure with broken inversion symmetry. The inequivalent valleys in the Brillouin zone could ...
We classify condensed matter systems in terms of the spacetime symmetries they spontaneously break. In particular, we characterize condensed matter itself as any state in a Poincare-invariant theory that spontaneously breaks Lorentz boosts while preserving ...
High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great challenge to fabricate nanoscopic high symmetry QDs is furt ...
This thesis works reports on the magnetic properties of single transition metal atoms and hydrogenated compounds adsorbed on crystal surfaces. It is an experimental study, based on scanning tunneling microscopy (STM), initiated by the project of demonstrat ...
We have investigated the magnetic structure in a polycrystalline sample of the B20-type MnGe by means of small-angle neutron scattering. On the projected diffraction plane normal to the incoming neutron beam, a Debye-ring-like pattern appears due to the ra ...
Novel magnetic materials are constantly emerging. This thesis reports an Electron Spin Resonance (ESR) study on three novel materials of great scientific interest: monoclinic SeCuO3 compound representing a network of tetramers, large assembly of ultrathin ...
A key property of equilibrium exciton-polariton condensates in semiconductor microcavities is the suppression of the Zeeman splitting under a magnetic field. By studying magnetophotoluminescence spectra from a GaAs microcavity, we show experimentally that ...
The time-reversal properties of charged systems in a constant external magnetic field are reconsidered in this paper. We show that the evolution equations of the system are invariant under a new symmetry operation that implies a new signature property for ...
We discuss equivariance for linear liftings of measurable functions. Existence is established when a transformation group acts amenably, as e.g. the Mobius group of the projective line. Since the general proof is very simple but not explicit, we also provi ...
A generalised time reversal symmetry for systems subject to a constant magnetic field is introduced, based on the analogy between the evolution equations of these systems and those of a system subject to shear. This generalisation makes it possible to deri ...
