Interactions in low-dimensional Dirac/Weyl-fermion systems (2D layered materials) (Prof. Krstić)

2D layered materials such as graphene, black phosphorus, SnSe, Sb2Te3 etc. are semi-metals or semiconductors, which due to their special electronic structure (e.g. Dirac and/or Weyl-like fermionic system) show a range of intriguing properties not occurring in conventional semiconductors and (semi)metals.
These properties are used in the context of, for instance, layer-number controlled band gaps, Dirac-Fermion optics, valleytronics and spintronics as well as include quantum and topology phenomena.
Our focus is on the investigation of phenomena that result from the various interactions within such low-dimensional systems. These include, for example, conductivity transitions due to layer-layer interactions not correlated with the band gap, Mie-like and valley-sensitive fermion scattering in periodic (magnetic) potentials, the formation of (macroscopic) quantum phases due to controllable effective Coulomb interaction as well as topological singularities in parity-breaking arrangements of layers.
Experimentally, we use physical and chemical methods to achieve and control (local and global) modification of the interactions between fermions in the layered materials. We investigate our own produced samples and components mainly by means of electrical transport.

Projects

Two-dimensional materials show enormous potential concerning application in electronic devices because of their extraordinary properties. The utilization of materials of this kind, however, is accompanied by significant challenges as layer-dependent propertiessubstantially determine potential device functionalities. These challenges are caused by an extensive lack of systematic studies investigating fabrication processes of electronic devices, including optimization, as well as resulting electrical…

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Project B12 aims to control the electronic (transport)properties of mono- and bilayer graphene and (reduced) graphene-oxide on surfaces using local and global strain. The first of two workpackages, WP-1, elucidates the electronic impact of covalent and non-covalent functionalisation at different strain by in-operandi (opto)electrical monitoring. Exploiting the unique valley-sensitivity of graphene (mono/bi) is subject of WP-2. Here local-strain induced topological and magnetic-field imposed…

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Low-dimensional carbon structures such as graphene and carbon nanotubes have raised tremendous interest in recent years both from fundamental and technological perspectives. However, the tunability of the density of electronic states of graphene and carbon nanotubes remains a limiting factor for their implementation in modern nanotechnology. It has been recently shown that the energy bandgap of graphene-based materials can be tailored via chemical modification of the graphene surface, e.g. by…

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Participating Scientists

Publications