[CCoE Notice] Upcoming Seminar: Material Program Seminar Announcement

[Hutchinson, Inez A]

[cid:image004.png at 01DA0671.E14111A0]Materials Engineering Program

Texas Center for Superconductivity at Univ. of Houston

Center for Integrated Bio and Nano Systems

10:00 am, Friday, Oct. 27, 2023

This seminar will be held in online only mode.

Zoom: https://urldefense.com/v3/__https://uh-edu-cougarnet.zoom.us/j/97136580701__;!!LkSTlj0I!G1CiOSglEK9m3Y_z6G9ky0EqjyaiJoT-M9TxPJmq4jH-TOXZiYhcnY3OD414wvs-c1MSkE10VaLUqDpaTxXmyKarce8$ 

Meeting ID: 971 3658 0701



Probing Dynamic Responses of Nano-Materials at the Boundary between  Classical and Quantum Mechanics detecting Coherent-Inelastic Electron Self-interferences

Christian Kisielowski1

1.Lawrence Berkeley National Laboratory, The Molecular Foundry, One Cyclotron Rd. Berkeley, CA 94720, USA

Abstract: The Copenhagen convention of quantum mechanics describes a boundary between the quantum world, where wave functions are indefinite in space and time, and the classical world of particles that we perceive as definite. Heisenberg’s Uncertainty Principle defines this boundary, but details about its relationship to electron-sample interactions remain incomplete. Specifically, it seems unfortunate that matters concerning wave-particle duality, time-dependent measurements, or the entanglement of wave functions and their collapse at a detector still require detailed investigations to enable progress. Certainly, this is no academic matter because such aspects become the bottleneck for the deployment of microscopes with high spatiotemporal resolution that already reaches towards ~ 1 Å spatial resolution with ~1 ps time resolution and enable investigations of dynamic processes in solids (1,2). With the development of aberration-correction, the characterization of static nano-materials by electron microscopy has made tremendous progress. The point is reached where single atoms can be chemically identified and detected in 3D that reveal beam-induced, dynamic behavior (3). Further, their operation in ultra-low dose conditions guaranties that only single electrons participate in scattering events (4), which allows maintaining the pristine structure of radiation sensitive matter. Here, we explore new principles by experimentally analyzing the relation between particle and wave descriptions of electron-matter interactions measuring the delocalization of an evanescent field in energy-filtered real-space images of sample/vacuum interfaces recorded. Its spatial extension coincides with the energy-dependent self-coherence length of propagating wave packets that obey the time-dependent Schrödinger equation and undergo a Goos-Hänchen shift. The wave packets are created by self-interferences during coherent-inelastic Coulomb interactions and exhibit a decoherence phase Δφ = 0.5 rad. Due to a reciprocal dependence on energy, they shrink below atomic dimensions for electron energy losses beyond 1000 eV when the wave packets appear particle-like. Consequently, atomic resolution observations inevitably include pulse-like wave propagations that stimulate structural dynamics at any electron energy loss.



Bio:  Dr. Christian Kisielowski was Principle Investigator and Staff Scientist at the Molecular Foundry, Lawrence Berkeley National Laboratory, CA. He was awarded his PhD in natural sciences (physics, mathematics, chemistry) and his Habilitation in experimental physics at the University of Cologne / Germany in 1985 and 1990, respectively, for performing spectroscopic studies of dislocations and point defects in semiconductors. Thereafter, he joint AT&T Bell Laboratories (1991 – 1994) where he invented new quantitative tools for image analyses in High Resolution Electron Microscopy. Since 1997, Dr. Kisielowski served as Staff Scientist at the NCEM where he developed and applied atomic resolution electron microscopy, sample preparation, and computational tools. He was the first to demonstrate sub-Ångstrom resolution in 1999 by mid-voltage phase contrast microscopy and reached record resolution below 0.5 Å, which touches the physical limits of obtainable resolution in electron microscopy. This achievement was established in 2009 within the TEAM Project of the Department of Energy (Transmission Electron Aberration-corrected Microscopy). Recognizing that beam-sample interactions and time resolution are now the most challenging aspects of atomic resolution electron microscopy, he developed a low dose rate technique, which enables time-resolved investigations of functionality on a single atom level in three dimensions and environmental meaningful conditions (elevated p, T). Such capabilities reach quantum mechanical limits and are of significant interest in the context heterogeneous systems for sustainable energy research that commonly contain soft and hard matter components including single-digit nanoparticles, two-dimensional materials, interfaces, surfaces or point and extended defects. Dr. Kisielowski has published over 200 peer reviewed articles including multiple publications in respected journals such as Science, Nature Materials, Nano Letters, Angewandte Chemie, Phys. Rev. Lett., and others. His h-index is 60. He retired from the LBNL in 2022 but remained affiliated and consults at different institutions.





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Xiaonan Shan, Ph.D.

Assistant Professor

Electrical and Computer Engineering Department

University of Houston

Houston, TX 77204, USA

Tel: 713-743-8593

Email: xshan at central.uh.edu<mailto:xshan at central.uh.edu>

Web: http://shanlab.ece.uh.edu/

[UNIVERSITY of HOUSTON - ECE]

[The Future is What We Do]


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