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News & Event

Seminar

(Oct 23rd) Spin Transport Physics in Dirac Matter & Valleytronics

Subject

Spin Transport Physics in Dirac Matter & Valleytronics

Date

2019.10.23 (Wed) 15:00

Speaker

Prof. Stephan Roche (Department of Theoretical and Computational Nanosciences, ICREA, Spain)

Place

Connect Room (2F), KI Building (E4), KAIST

Overview:

 Lecture 1)  Spin Transport Physics in Dirac Matter

   In this Lecture, I will present some foundations of spin transport for Dirac fermions propagating in supported graphene devices or interfaced with strong SOC materials. The role of entanglement with “valley and sublattice pseudospins” in tailoring the spin dephasing and relaxation mechanisms will be explained as well as the impact of strong SOC proximity effects on spin lifetime anisotropy, weak antilocalization and topological transport phenomena such as Spin Hall effect and Quantum spin Hall effects. Recent results showing universal spin diffusion length in polycrystalline Graphene and nonlocal resistance transport phenomena in the crossover from ballistic to diffusive regimes will be also introduced. 

 

   Lecture 2)  Valleytronics

   The presence of extra degrees of freedom (sublattice pseudospin, valley isospin) in Dirac Matter and van der Waals heterostructures points towards new directions for information processing, extending the playground to valleytronics, multifunctional electronic devices or novel quantum computing paradigms harnessing all these degrees of freedom in combination with electromagnetic fields or other external fields (strain, chemical functionalization).  I will present a critical discussion about the ongoing debate about the realization and control of valley Hall effect (and quantum valley Hall effect) in two-dimensional-based materials and heterostructures and show the various theoretical proposals 

Profile:

ICREA Research Professor (since September 2010)

CATALAN INSTITUTE OF NANOSCIENCE and NANOTECHNOLOGY

Head of the Theoretical and Computational Nanoscience Group

Campus de la UAB, 08193 Bellaterra, Barcelona (Spain)