Giovedì 19 settembre alle ore 15.00 si terrà il Seminario "Electronic properties of zigzag edges of molybdenum disulfide MoS2" in Aula A1, 3° piano, Edificio C11

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19/09/2019 - 15:00
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19/09/2019 - 18:00
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16/09/2019

AVVISO DI SEMINARIO

 

Prof. Philippe Lambin

 

Department of Physics, University of Namur, Belgium

 

Electronic properties of zigzag edges of molybdenum disulfide MoS2

 

19 settembre 2019, ore 15.00

Aula A1, 3° piano, Edificio C11

 

Summary: Transition metal dichalcogenides, and particularly molybdenum disulfide (MoS2), are among the most intensively studied 2D materials owing to their direct band gap, which makes them good candidates for electronic and optoelectronic applications. MoS2 is a nonmagnetic semiconductor. However, several early theoretical studies have predicted magnetic moments localized on the edges of zigzag  nanoribbons similar to the case of zigzag graphene nanoribbons. On the experimental side, recent magnetic measurements on large scale growth of zigzag MoS2 nanoribbons demonstrate prominent ferromagnetic behavior. In view of these observations, it is important to explore the properties of edge magnetism in MoS2 nanoribbons, especially in large systems where disorder cannot be excluded.

For systems involving a large number of atoms, tight-binding (TB) approach is a suitable alternative to ab-initio calculations. TB can provide a simple starting point for further inclusion of many-body electron-electron effects. By using parameters finely adjusted to DFT band structures together with local Coulomb interactions (the so-called Hubbard, U), the magnetic properties of the MoS2 nanoribbons have been investigated with a TB+U Hamiltonian. The calculations reveal a small domain-wall energy that indicates a weak magnetic coupling between the edge atoms, in remarkable contrast with zigzag graphene nanoribbons. By using randomly distributed Gaussian potentials, the effects of disorder on the magnetic properties have been investigated. Playing with the spatial disorder extension makes it possible to flip the orientation of the edge magnetic moments almost at will.[1]

 

Short biography: Engineer in physics from the university of Liège (B)and doctor in physics from the same university. Associate member of the Funds for Scientific Research of Belgium till 1995, then professor at the physics department of the university of Namur (B). Emeritus from that university since February 2019. Since October 2018, full professor at the Pedagogical Higher Education Institute of Bukavu, (Democratic Republic of Congo). Ordinary member of the Royal Academy of Belgium since 2013. About 400 publications in theoretical condensed matter physics and nanosciences.



[1])    Stability of edge magnetism against disorder in zigzag MoS2 nanoribbons, P. Vancsó, I. Hagymàsi, P. Castenetto, and Ph. Lambin, Phys. Rev. Mater. 3 (2019) 094003.

Ultimo aggiornamento: 16-09-2019 - 14:55
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