ORALS

SESSION: EnergyThuPM1-R11	6th Intl. Symp. on Sustainable Energy Production: Fossil; Renewables; Nuclear; Waste handling , processing, and storage for all energy production technologies; Energy conservation
Thu Oct, 24 2019 / Room: Coralino
Session Chairs: Udo Schwingenschlogl; Tunc Aldemir; Session Monitor: TBA

14:00: [EnergyThuPM105]
Proximity-Induced Spin-Valley Polarization in Silicene or Germanene on F-Doped WS2
Udo Schwingenschlogl¹ ; Shahid Sattar¹ ; Nirpendra Singh¹ ; ¹King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia;
Paper Id: 23 [Abstract]

Silicene and germanene are key materials for the field of valleytronics. Interaction with the substrate, however, which is necessary to support the electronically active medium, becomes a major obstacle. In the present work, we propose a substrate (F-doped WS₂) that avoids detrimental effects and, at the same time, induces the required valley polarization, so that no further steps are needed for this purpose. The behavior is explained by proximity effects on silicene or germanene, as demonstrated by first-principle calculations. Broken inversion symmetry due to the presence of WS₂ opens a substantial band gap in silicene or germanene. F doping of WS₂ results in spin polarization which, in conjunction with proximity-enhanced spin-orbit coupling, creates sizable spin-valley polarizations.

References:
Physical Review B 94, 205415 (2016)

SESSION: AdvancedMaterialsThuPM2-R2	5th Intl. Symp. on New and Advanced Materials and Technologies for Energy, Environment and Sustainable Development
Thu Oct, 24 2019 / Room: Leda (99/Mezz. F)
Session Chairs: Fernand Marquis; Udo Schwingenschlogl; Session Monitor: TBA

16:20: [AdvancedMaterialsThuPM210] Keynote
Elemental 2D Materials beyond Graphene: Insights from Computational Theory
Udo Schwingenschlogl¹ ; ¹King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia;
Paper Id: 50 [Abstract]

The presentation will address recent developments related to elemental 2-D materials beyond graphene, with a focus on silicene, germanene, and arsenene. Several examples will be discussed in order to illustrate how computational theory based on first-principles calculations can contribute to the understanding of basic physical and chemical phenomena in 2-D condensed matter. Silicene is of particular interest due to its compatibility with established Si technology. Regrettably, strong interaction with common substrates eliminates the Dirac states. Alternative substrates will be analyzed and the effects on silicene will be evaluated with respect to technological requirements. Germanene attracts more and more attention because the effects of spin-orbit coupling are accessible in contrast to lighter 2-D materials. While the same is true for arsenene, the material's strongly buckled structure is not compatible with Dirac physics. Recovering the sp² bonding, on the other hand, makes it possible to realize unusual properties.

References:
1. ACS Applied Materials & Interfaces 6, 11675-11681 (2014)
2. Journal of Materials Chemistry C 3, 3946-3953 (2015)
3. 2D Materials 2, 045004 (2015)
4. Physical Review B 93, 045312 (2016)
5. Physical Review B 94, 205415 (2016)