When
Presenter:
Dr. Andre Schleife
Associate Professor, Department of Materials Science & Engineering,
University of Illinois
Abstract:
Multi-length and time-scale relaxation processes connect non-equilibrium excited electrons in a target material after ion or electron irradiation with characteristic properties when they are emitted as secondary electrons. The focus will be on graphene as a prototypical two-dimensional material for which I will discuss the regimes of high electron and lattice temperatures. Our simulations show that lattice temperature significantly increases secondary electron emission, whereas electron temperature has a negligible effect. I will discuss the early stages, in which secondary electrons emitted within a few femto-seconds after ion impact can be of use as high-resolution thermalization probes. The classical and quantum mechanical regime of projectile electrons will be derived from real-time time-dependent density functional theory simulations.
In addition, the promise of extreme computing power associated with future quantum computers motivates researchers across many fields to explore currently existing noisy intermediate scale quantum computers and characterize their use and limitations. In this talk I will show recent examples of electronic-structure simulations, using quantum defect embedding theory, to bridge the gap between small numbers of Qbits and large numbers of atoms in a typical materials system, such as near-surface oxygen vacancies in α-Al2O3. Studies on quantum simulators show promising results and noise is the limiting factor when running on quantum hardware. Zero-noise extrapolation is discussed as a scheme to mitigate this noise.
Bio:
André Schleife is a Blue Waters Professor in Materials Science and Engineering at the University of Illinois at Urbana-Champaign. He obtained his Diploma and Ph.D. at Friedrich-Schiller-University in Jena. He then was a Postdoctoral Researcher at Lawrence Livermore National Laboratory before starting at Illinois in 2013. He received the NSF CAREER award, the ONR YIP award, and was an ACS PRF doctoral new investigator. André actively organizes national and international schools, workshops, and tutorials to advance the community around cutting-edge first-principles simulations of materials. He is co-chair of the Gordon Research Conference on “Computational Materials Science”, Vice Chair of the Division of Computational Physics of the American Physical Society, and the co-lead of the Quantum Thrust of the IBM Illinois Discovery Accelerator.
Hosted by: Dr. Tom Purcell