Final Report Summary - MOMB (Magneto-optics of layered materials: exploring many-body physics in electronic systems with unconventional bands)
The ERC MOMB project has been devoted to studies of electronic properties of graphene-based structures, topological insulator and 3D Dirac materials as well as mono-, multi-layers and bulk crystals of transition metal dichalcogenides (TMD). Elucidation of the band structures and clarification of the role of interactions (electron-phonon electron-electron and symmetry breaking effect) in these emerging systems were among the main objectives of the project. The leading experimental technique used for the studies has been optical magneto-spectroscopy (far-infrared to visible spectral range), supported when necessary by magneto-transport methods.
On the technical side, the project resulted in a successful development of the new experimental set-up for micro-magneto-Raman scattering measurements and of the efficient capability of the in-house fabrication, by methods of mechanical exfoliation, of structures made of atomically thin layers (extracted from graphite and TMD crystals).
Altogether, the project resulted in >45 scientific papers, including those in Nature (1), Science (1), Nature Physics (3), Nature Nanotechnology (1), Nature Communications (2), Nano Letters (8), Physical Review X (1), Physical Review Letters (3), Nanoscale (3), and 2D Materials (6).
The list of main research achievements (fully or partially) resulted from the project includes:
- demonstration of the tunability of magneto-phonon resonances with carrier density in gated graphene [Nano Lett. 14, 1460 (2014)],
- demonstration of novel class, of multiple magneto-phonon resonances in graphene [2D Materials 3, 015004 (2016)],
- identification of the electronic magneto-Raman response in mono-, bi-, tri-, tetra, and penta-graphene [Nano Lett. 14, 4548 (2014)],
- demonstration of the strong efficiency of the Auger recombination of photo-excited carriers in the lowest Landau levels of graphene [New J. Phys. 16, 123021 (2014); Nature Phys. 11, 75 (2015)],
– comprehensive description (experiment and theory) of the effects of electron-electron interactions on energy bands and inter Landau level excitations in graphene [PRL 114, 126804 (2015)],
– demonstration of the fractal pattern of Landau levels (Hofstadter butterfly), in graphene with superimposed periodic potential [Nature 497, 594 (2013); Nature Phys. 10, 525 (2014)],
– demonstration of the bandgap opening (driven by electron – electron interactions) in tetra-graphene [Nature Commun. 6, 6419 (2015)],
- demonstration of the chirality effects with magneto-tunneling between weakly misaligned two-graphene sheets [Science 353, 575 (2016)],
- elucidation of the energy bands and magnetic ordering in rhombohedral graphene stacks [Nano Lett. 16, 3710 (2016), arXiv:1708.03220]
– clarification of the band structure of a representative topological insulator, Bi2Se3 [PRL 114, 186401 (2015); PRB 91, 081104(R) (2015); Sci. Rep. 6, 19087 (2016); Sci. Rep. 7, 6891 (2017); EPL 117, 47006 (2017)],
- elucidation of the energy bands of a representative 3D Dirac material, Cd3As2 [PRL 117, 136401 (2016); PRB 97, 115206 (2018)],
- observation of three dimensional massless Kane fermions in zinc-blende crystals (CdHgTe) [Nature Phys. 10, 233 (2014)],
- characterization of the optical response in mono- multi- and bulk crystals of MoTe2, WSe2, MoSe2, and WS2 [Nano Lett. 15, 2336 (2015); Nanoscale 7, 10421, (2015); Nanoscale 7, 20769, (2015); Nanoscale 9, 13128, (2017)],
- discovery of single photon emitters in thin layers of WSe2[Nature Nanotech. 10, 503 (2015)],
- demonstration of the tunability of the valley polarization in WSe2 and WS2 monolayers with with a tiny magnetic field [PRX 6, 021024 (2016), 2D Materials 5, 015023 (2018)],
- clarification of the excitonic Zeeman effect in S-TMD monolayers [Nano Lett. 16, 3624 (2016), arXiv:1803.00376]
- revealing the interlayer excitons in bulk MoTe2 [Nature Commun. 8, 1703 (2017)],
- demonstration of dark excitons in WSe2 and WS2 monolayers [Nanoscale 7, 10421, (2015);2D Materials 4, 021003 (20178)],
– elucidation of the complex dynamics of excitons, largely affected by disorder, in MoSe2 and WS2 monolayers [Nano Letters 16, 5333 (2016); arXiv:1709.03220].
On the technical side, the project resulted in a successful development of the new experimental set-up for micro-magneto-Raman scattering measurements and of the efficient capability of the in-house fabrication, by methods of mechanical exfoliation, of structures made of atomically thin layers (extracted from graphite and TMD crystals).
Altogether, the project resulted in >45 scientific papers, including those in Nature (1), Science (1), Nature Physics (3), Nature Nanotechnology (1), Nature Communications (2), Nano Letters (8), Physical Review X (1), Physical Review Letters (3), Nanoscale (3), and 2D Materials (6).
The list of main research achievements (fully or partially) resulted from the project includes:
- demonstration of the tunability of magneto-phonon resonances with carrier density in gated graphene [Nano Lett. 14, 1460 (2014)],
- demonstration of novel class, of multiple magneto-phonon resonances in graphene [2D Materials 3, 015004 (2016)],
- identification of the electronic magneto-Raman response in mono-, bi-, tri-, tetra, and penta-graphene [Nano Lett. 14, 4548 (2014)],
- demonstration of the strong efficiency of the Auger recombination of photo-excited carriers in the lowest Landau levels of graphene [New J. Phys. 16, 123021 (2014); Nature Phys. 11, 75 (2015)],
– comprehensive description (experiment and theory) of the effects of electron-electron interactions on energy bands and inter Landau level excitations in graphene [PRL 114, 126804 (2015)],
– demonstration of the fractal pattern of Landau levels (Hofstadter butterfly), in graphene with superimposed periodic potential [Nature 497, 594 (2013); Nature Phys. 10, 525 (2014)],
– demonstration of the bandgap opening (driven by electron – electron interactions) in tetra-graphene [Nature Commun. 6, 6419 (2015)],
- demonstration of the chirality effects with magneto-tunneling between weakly misaligned two-graphene sheets [Science 353, 575 (2016)],
- elucidation of the energy bands and magnetic ordering in rhombohedral graphene stacks [Nano Lett. 16, 3710 (2016), arXiv:1708.03220]
– clarification of the band structure of a representative topological insulator, Bi2Se3 [PRL 114, 186401 (2015); PRB 91, 081104(R) (2015); Sci. Rep. 6, 19087 (2016); Sci. Rep. 7, 6891 (2017); EPL 117, 47006 (2017)],
- elucidation of the energy bands of a representative 3D Dirac material, Cd3As2 [PRL 117, 136401 (2016); PRB 97, 115206 (2018)],
- observation of three dimensional massless Kane fermions in zinc-blende crystals (CdHgTe) [Nature Phys. 10, 233 (2014)],
- characterization of the optical response in mono- multi- and bulk crystals of MoTe2, WSe2, MoSe2, and WS2 [Nano Lett. 15, 2336 (2015); Nanoscale 7, 10421, (2015); Nanoscale 7, 20769, (2015); Nanoscale 9, 13128, (2017)],
- discovery of single photon emitters in thin layers of WSe2[Nature Nanotech. 10, 503 (2015)],
- demonstration of the tunability of the valley polarization in WSe2 and WS2 monolayers with with a tiny magnetic field [PRX 6, 021024 (2016), 2D Materials 5, 015023 (2018)],
- clarification of the excitonic Zeeman effect in S-TMD monolayers [Nano Lett. 16, 3624 (2016), arXiv:1803.00376]
- revealing the interlayer excitons in bulk MoTe2 [Nature Commun. 8, 1703 (2017)],
- demonstration of dark excitons in WSe2 and WS2 monolayers [Nanoscale 7, 10421, (2015);2D Materials 4, 021003 (20178)],
– elucidation of the complex dynamics of excitons, largely affected by disorder, in MoSe2 and WS2 monolayers [Nano Letters 16, 5333 (2016); arXiv:1709.03220].