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X-WR-CALNAME:LASSP/AEP Seminar: Heiki Pfau (Penn St.)
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260810T173837Z
UID:tag:localist.com\,2008:EventInstance_50595330789133
DTSTART:20250916T162000Z
DTEND:20250916T171000Z
DESCRIPTION:The revival of Fe-based superconductors: cascades of screening 
 processes and their implications\n\nUnderstanding how renormalized quasipa
 rticles emerge in strongly correlated electron materials provides a challe
 nge for both experiment and theory. It has been predicted that distinctive
  spin and orbital screening mechanisms drive this process in multiorbital 
 materials with strong Coulomb and Hund’s interactions. In this talk I wi
 ll focus on hole-doped iron-based superconductors AFe2As2 (A=Rb\,Cs)\, whi
 ch are the most correlated members of this material class with large effec
 tive masses and strongly renormalized band dispersions. It is currently de
 bated which role electronic correlations play in the complex phase diagram
 s of iron-based materials that contain unconventional superconducting\, ne
 matic\, and magnetic phases as well as strange metal behavior.\n\nIn our a
 ngle-resolved photoemission spectroscopy (ARPES) study\, we observe the ex
 istence of two screening processes. The emergence of low-energy Fe 3dxy qu
 asiparticles at low temperatures is tied to spin screening. A second proce
 ss changes the spectral weight at high energies up to room temperature. Su
 pported by material-specific and model calculations\, we propose that orbi
 tal screening of Fe 3d atomic excitations is responsible for it. These two
  cascading screening processes drive the temperature evolution from a bad 
 metal to a correlated Fermi liquid [1\,2].\n\n[1] M-H. Chang et al.\, Natu
 re Comm. 15\, 9958 (2024).\n[2] M-H. Chang et al.\, Commun. Mater 6\, 157 
 (2025).\n \n\nBio: Heike Pfau is an assistant professor of physics at The 
 Pennsylvania State University. She received her Ph.D. in physics from the 
 Technical University Dresden & Max-Planck Institute CPfS in Dresden\, Germ
 any in 2015. Prior to that\, she earned her Diploma Physics from the Techn
 ical University Dresden in 2010.\n\nPfau’s research focuses on materials
  with strong electronic correlations. These materials develop novel phenom
 ena and unconventional electronic phases such as heavy fermion behavior\, 
 unconventional superconductivity\, nematicity\, and quantum criticality. S
 he wants to advance the knowledge of such emergent collective phenomena us
 ing angle-resolved photoemission spectroscopy (ARPES) as well as low tempe
 rature transport and thermodynamic probes. Her  main focus lies on correla
 ted materials containing transition metal or rare-earth elements such as h
 eavy fermion systems and iron-based superconductors.
GEO:42.449741;-76.481209
LOCATION:Clark Hall\, 700
SUMMARY:LASSP/AEP Seminar: Heiki Pfau (Penn St.)
URL;VALUE=URI:https://events.cornell.edu/event/lasspaep-seminar-heiki-pfau-
 penn-st
CATEGORIES:Seminar
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