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Projekt Druckansicht

Theoretische Untersuchung des elektronischen Transports in funktionalisierten 2D Übergangsmetalldichalcogeniden

Fachliche Zuordnung Theoretische Physik der kondensierten Materie
Herstellung und Eigenschaften von Funktionsmaterialien
Theoretische Chemie: Elektronenstruktur, Dynamik, Simulation
Förderung Förderung von 2015 bis 2021
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 280173823
 
Erstellungsjahr 2019

Zusammenfassung der Projektergebnisse

The Trans2DTMD aims to develop on one hand novel numerical methods for transport calculations in 2D materials, on the other hand it also aims to investigate the effects of defects and strains on the properties of metallic TMDs and to predict novel 2D materials with interesting properties, e.g. with topological properties. Such properties are of utmost importance in electronics applications, e.g. field effect transistors, photovoltaic applications or bio-sensors. The main objectives of the project are the following: 1. Investigate electronic properties and stability metallic TMDs (intrinsic, by doping or by inducing topological surface/interface states). 2. Predict and investigate novel 2D materials and their heterostructures with TMDs 3. Develop linear O(N) numerical methods for a) the conductivity tensor (longitudinal/transverse, spin and valley) b) non-equilibrium Green’s functions approach (using Chebyshev expansions) 4. Describe electrical and spin-polarized transport through magnetically doped TMDs and ferromagnetic alloy/graphene interfaces in the presence of spin-orbit couplings 5. Propose and describe new devices/contact geometries based on TMDs The project has successfully achieved its objectives: 1) Significant advances in numerical codes have been achieved. o Besides new functionalities added to the Pybinding code, developed at U. Antwerp (docs.pybinding.site/en/stable), we have been part of the development team of the KITE open source software (quantum-kite.com). We have implemented efficient codes that can take advantage of state-of-the-art computational resources: computer clusters and video cards (GPU). This allows for the investigation of generic systems where disorder effects on the electrical and optical conductivity of 2D materials.  this software is available as open source code to the research community  it allows the simulation of very large systems at tight-binding level (billions of atoms), to capture effects seen in experimentally relevant mesoscopic samples (weak localization, diffuse regimes, etc). This is important since many of the theoretical tools fail in the case of adatoms and defects since these are strong scatterers.  it allows for accurate spintronics and valleytronics simulations since both spin and valley components of the conductivity tensor are available.  it is general and accurate, through the use on input from DFT simulations and the automatic setup of tight-binding models by using Wannier maximally localized orbitals or the Slater Koster approach. This has been implemented in the TB Studio software (tight-binding.com) developed at UA by M. Nakhaee. o first principles spin transport methods have been developed allowing for the calculation of transport properties of magnetic materials, including thermal, alloy disorder, noncollinearity and spin-orbit coupling effects. 2) A considerable focus was dedicated to DFT calculations of novel 2D materials were performed and revealed a new set of interesting materials showing, anisotropic behavior (WSe2, TiSe3, ZrS3), high carrier mobility (GeP3, Tl2O, haeckelite NbS2), metallic monolayer PtTe, ferroelastic and topological insulator haeckelite structure of MSSe (M=Mo,W), double Dirac points (Ta2S3), intrinsic magnetism (penta-hexa-graphene, doped MoS2 and fluorographene), etc. 3) Intense collaborations with experimental and theoretical Graphene core partners resulted in joint high impact publications. For example: o “Defect healing and charge transfer – mediated valley polarization in MoS2/MoSe2/MoS2 trilayer van der Waals heterostructures”, work done in collaboration with A. Kis appeared in Nano Letters (doi:10.1021/acs.nanolett.7b00904) o “Gate induced monolayer behavior in twisted bilayer black phosphorus”, work done in collaboration with J.R. Wallbank appeared in 2D Materials (doi: doi:10.1088/2053- 1583/aa80c4) o “Ballistic electron channels including weakly protected topological states in delaminated bilayer graphene”, work done in collaboration with J.R. Wallbank and V. Falko appeared in Phys. Rev. B (doi:10.1103/PhysRevB.97.045301) o “Dependence of the shape of graphene nanobubbles on trapped substance”, work done in collaboration with K. Novoselov appeared in Nature Communications (doi:10.1038/ncomms15844) o “Composite super-moiré lattices in double aligned graphene heterostructures, to appear in Science Advances (2019). Work done in collaboration with A.K. Geim and K. Novoselov. o “Non-equilibrium anistotropic excitons in ReS2”, work done in collaboration with A. Kis, appeared in 2D materials (doi: 10.1088/2053-1583/aae9b9). The full list of publications resulting from the Trans2DTMD project can be accessed at http://nano.uantwerpen.be/2dtmd_publ.

Projektbezogene Publikationen (Auswahl)

 
 

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