Ultrafast excited state dynamics in low dimensional

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Elementary interactions in solids,Coupling between the. various degrees,of freedom,Orbital tomography,Time and angle resolved in 2D adsorbate. photoemission layers,spectroscopy,Pump pulse creates non equilibrium state. Probe pulse monitors photoinduced dynamics,at variable time delays EVac. ARPES from a laser excited sample,Energy and momentum resolution EF.
Transient electronic structure probed by trARPES,Snapshots of the the electronic structure Eb. for different time delays,Record movies of photoinduced changes. of the electronic band structure E kx ky t,see e g F Schmitt et al Eb const. Science 321 1649 2008 kx,2Dmaterials, Charge density wave formation Metal to insultor transitions. resistivity cm,temperature K,Spin valley layer correlation.
Prototypical,Main interactions systems,Electron phonon coupling TaS2. Coulomb correlations TiSe2,Excitonic effects TbTe3. Spin orbit coupling MoS2,Why ultrafast spectroscopy. my biased view,Phase transitions and ultrafast dynamics. Phase transitions in solids Ultrafast photoexcitation. near equilibrium non quilibrium,insulator TaS2 Crossover.
resistivity,4 kT optical,2 excitation,metal 0 01,1 0 1 2 1 4 1 6 1 8. temperature U W, What can be learned from bringing the system out of equilibrium. Timescale to induce a transition to a non equilibium state. Spectroscopy of such excited states and new phases. Sipos et al for the,Nature Mater return,2008 equilibrium. Scattering processes in excited states, Hierarchy of timescales of ultrafast processes in solids. linewidth eV Example e e scattering,1 0 1 0 01 0 001.
screening nuclear,e correlation,e e scattering,electronic. e ph scattering,vibrations,0 1 1 10 100 1000,Timescale fs. Elementary scattering processes,Note that electrons and ions in solids are. screened by surrounding charge density electron electron scattering. screended Couloub interaction low energy excitations. electron phonon scattering,concept of quasiparticles. electron magnon scattering,Photoinduced phase trasitions.
Hierarchy of timescales of ultrafast processes in solids. linewidth eV Example Metal Insulator transition,1 0 1 0 01 0 001. screening nuclear,dephasing motions,e correlation,e e scattering. electronic,e ph scattering,vibrations,0 1 1 10 100 1000. Timescale fs,Mechanistic understanding from ultrafast dyamics. Timescale to induce the transition to a different phase. Probe the dynamics of the order parameter e g gap closing. Momentum dependent scattering in excited states, Intervalley scattering of optically excited carriers in semiconductors.
Okamoto et al Nature Mater 13,Enhanced Spin Hall,effect in GaAs. Spin and Valleytronics in TMDCs,R Bertoni et al arXiv 1606 03218. Orbital tomography in 2D adsorbate layers, Molecular orbital reconstruction from photoelectron angular distributions. Pentancene Ag,Puschnig et al,Science 326 703 2009, 3D reconstruction Wei et al Nature Commun 6 8287 2015. What about ultrafast dynamics and excited states,Orbital tomography in 2D adsorbate layers.
What about ultrafast dynamics and excited states, Challenge From understanding of static electronic structure. Puschnig et al,Science 326 703, to dynamics of electronic excitations and charge transfer. Examples Excited states singlet triplet conversion electron nuclear. coupling interfacial charge transfer phase transitions more. Ultimate goal Excited state structural dynamics and microscopy. incomplete biased,history of,time resolved photoemission. Time resolved ARPES the early days,pulse width 50 ps. harmonic generation,in Xe hv 10 5 eV,surface state.
100 ps time,Time resolved ARPES the early days,pulse width 850 fs. Dynamics of intervalley,scattering in GaAs,on 2 ps time scale. Martin Wolf Fritz Haber Institut of the Max Planck Society Berlin Germany Ultrafast excited state dynamics in low dimensional materials probed by time resolved ARPES International Research School IMPACT 2016 Cargese 23 8 2 9 2016

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