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SUMMARY:MechE Seminar: Thermal transport and mechanical properties of ener
 gy materials by non-contact laser-based techniques
DTSTART:20220215T090000
DTEND:20220215T100000
DTSTAMP:20260916T062935Z
UID:782f6d4d4e389446365f0b6b0aa70f9647f3b7cc63fe8edadc6d7cf0
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Begoña Abad Mayor\, Nanophononics Lab\, Department of Phy
 sics\, University of Basel\nAbstract: Nanofabrication techniques now make 
 it possible to synthesize materials with atomic-scale characteristics. At 
 these sizes\, traditional models fail to predict the fundamental propertie
 s of materials\, thus new experimental and theoretical tools are needed in
  order to discover new physics. Phonons—vibrations of the atomic lattice
 —are responsible for sound and heat propagation\, and behave radically d
 ifferently in nanostructured systems. Controlling phonons is key for engin
 eering both mechanical and thermal properties\, critical to lightweight an
 d energy-efficient nano-electronics\, thermoelectric devices\, photovoltai
 cs\, and sensors. However\, measuring thermal transport at the nanoscale i
 s especially difficult due to small\, localized temperature gradients as w
 ell as significant thermal contact resistances. Measuring nondestructively
  mechanical properties at the nanoscale is also challenging due to substra
 te influence and difficult control over the applied tensile stress\, yet i
 t is needed for designing compliant devices. To overcome these challenges\
 , non-contact laser-based metrology techniques are used nondestructively t
 o access these properties. In particular\, the frequency-resolved photoaco
 ustic effect enables the measurement of the thermal conductivity of a wide
  range of materials\, while time-resolved techniques based on pump-probe s
 chemes are ideal to access the fundamental mechanism of thermal transport 
 in various materials. Here\, I will present advances in both characterizat
 ion of thermal properties of thermoelectric materials [1]\, as well as the
  understanding of non-diffusive heat flow away from nanoscale sources [2].
  Additionally\, I will show how we extended these measurements to probe th
 e mechanical and structural properties of ultrathin films and complex meta
 lattices [3\,4]. Finally\, I will present recent efforts in the developmen
 t of a versatile technique based on transient reflectivity and time-resolv
 ed Raman spectroscopy to characterize carrier and lattice dynamics as well
  as different regimes of thermal transport.\n\n[1] M. Muñoz-Rojo*\, B. Ab
 ad*\, C. V. Manzano\, J. Maiz\, L. Vera\, X. Alvarez\, and M. Martín Gonz
 alez. “Thermal conductivity of Bi2Te3 nanowires: how size affects phonon
  scattering”\, Nanoscale\, 2017\, 9\, 6741-6747.\n[2] Beardo\, J. L. K
 nobloch\, L. Sendra\, J. Bafaluy\, T. D. Frazer\, W. Chao\, J. N. Hernande
 z-Charpak\, H. C. Kapteyn\, B. Abad\, M. M. Murnane\, F. X. Alvarez\, and 
 J. Camacho. A General and Predictive Understanding of Thermal Transport fr
 om 1D- and 2D-Confined Nanostructures: Theory and Experiment”. ACS Nano\
 , 2021\, 15 (8)\, 13019-13030. \n[3] T. D. Frazer\, J. L. Knobloch\, J. N
 . Hernández-Charpak\, K. M. Hoogeboom-Pot\, D. Nardi\, S. Yazdi\, W. Chao
 \, E. H. Anderson\, M. K. Tripp\, S. W. King\, H. C. Kapteyn\, M. M. Murna
 ne\, B. Abad. “Full characterization of ultrathin 5nm low-k dielectric 
 bilayers: Influence of dopants and surfaces on the mechanical properties
 ”. Physical Review Materials\, 4\, 073603 (2020).\n[4] B. Abad\, J. Knob
 loch\, T. Frazer\, J. Hernández-Charpak\, H. Cheng\, A. Grede\, N. Gieb
 ink\, T. Mallouk\, P. Mahale\, W. Chen\, Y. Xiong\, I. Dabo\, V. Crespi\
 , D. Talreja\, V. Gopalan\, J. Badding\, H. Kapteyn\, M. Murnane.  “N
 ondestructive measurements of the mechanical and structural properties of 
 nanostructured metalattices” Nano Letters\, 20\, 5\, 3306-331 (2020)\n\n
 Bio: Begoña Abad received her PhD in Physics from the Complutense Univers
 ity of Madrid for research carried out in the Institute of Micro and Nanot
 echnology of the Spanish National Research Council (IMN-CSIC\, Spain). Her
  thesis work focused on the development of thermal property measurement te
 chniques to characterize the efficiency of thermoelectric materials. In 20
 16 she moved to the University of Colorado Boulder (USA) where she joined 
 the Kapteyn-Murnane group at JILA. She used coherent extreme ultraviolet l
 ight to investigate phonon and acoustic dynamics of nanoscale materials. S
 he is currently a Marie Skłodowska-Curie fellow at the Nanophononics grou
 p at the University of Basel where she implemented a versatile technique t
 hat combines transient reflectivity with time-resolved coherent and sponta
 neous Raman spectroscopy techniques to explore energy flow and hydrodynami
 c thermal transport in bulk and nanoscale systems.
LOCATION:https://epfl.zoom.us/j/69176751374
STATUS:CONFIRMED
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