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CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:4
UID:UW-Physics-Event-9531
DTSTART:20261113T213000Z
DTEND:20261113T223000Z
DTSTAMP:20261104T075548Z
LAST-MODIFIED:20261022T160025Z
LOCATION:Chamberlin 2241 - https://uwmadison.zoom.us/j/96927300636?pwd
 =2Gjt5BXqG7T3FfvBQ8C5okcNldSzzn.1
SUMMARY:X-rays Meet Quantum Tunneling: A Journey to Single-Atom Spectr
 oscopy\, Physics Department Colloquium\, Volker Rose\, Argonne Nationa
 l Laboratory
DESCRIPTION:How do we identify a single atom using X-rays? This colloq
 uium will explore the fundamental
\nphysics of X-rays and their intera
 ction with matter\, leading to the ability to investigate individual
\
 natoms through X-ray spectroscopy. Beginning with an introduction to X
 -ray generation\,
\nsynchrotron radiation\, and conventional X-ray mic
 roscopy\, we will explore how X-rays reveal the
\nstructure\, chemistr
 y\, and physical properties of materials.
\nI will then share the scie
 ntific journey of developing Synchrotron X-ray Scanning Tunneling
\nMi
 croscopy (SX-STM)\, a technique that my team and I have pursued over m
 uch of my professional
\ncareer. By combining the elemental\, chemical
 \, and magnetic sensitivity of synchrotron X-rays with
\nthe atomic-sc
 ale spatial resolution of scanning tunneling microscopy\, SX-STM exten
 ds X-ray
\nspectroscopy beyond the spatial resolution limits of conven
 tional X-ray microscopy. Through the
\ndetection of X-ray-excited tunn
 eling currents\, we have achieved X-ray spectroscopic
\ncharacterizati
 on of individual atoms\, enabling the determination of their elemental
  identities and
\nlocal chemical states. I will discuss the experiment
 al challenges and breakthroughs that made these
\nmeasurements possibl
 e\, followed by recent advances in studying chemically complex materia
 ls\,
\nresolving magnetism at the atomic-layer level\, and exploring t
 he magnetic properties of individual
\natoms.
\nThe underlying concept
 s\, light-matter interactions\, quantum tunneling\, and magnetism\, co
 nnect to
\nfundamental questions across physics. The goal of this coll
 oquium is to make these ideas accessible
\nto a broad audience while i
 llustrating how scientific curiosity and experimental innovation can p
 ush
\nthe boundaries of what we can measure.
\nThis work was performed
  at the Advanced Photon Source and the Center for Nanoscale Materials\
 , U.S. Department of
\nEnergy Office of Science User Facilities\, unde
 r Contract No. DE-AC02-06CH11357.
\n[1] Nature 618\, 69–73 (2023).
\
 n[2] Advanced Materials 36\, 2402442 (2024).
\n[3] Physical Review Mat
 erials 10\, L091401 (2026).
URL:https://www.physics.wisc.edu/events/?id=9531
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