Department of Physics and Astronomy, University of Pittsburgh and Luo Jia Chair, Wuhan University
Space-periodic arrangement of lattice ions in crystalline solids defines the k-momentum dispersion of electronic quasiparticle bands. Light can interrogate such bands by stimulating electronic dipole transitions, however, when its time-periodic interaction exceeds all other perturbations, particularly at an optical resonance, it can manipulate the system eigenstates causing the crystal band structure to be dressed. The electronic bands become replicated by Floquet engineering, and are shifted by the AC Stark effect. I will describe how we control optical fields with attosecond precision to instantaneously shift and modify electronic bands of Cu(111) surface on sub-optical cycle time scales. I will demonstrate entanglement between optical fields and k-dispersions that can modify and control the quasiparticle properties, such as band energies and transport masses, and therefore, all electronic properties that depend on them. I will also explore the possibility to design and control the quasiparticle properties of quantum materials by light. The chemical interactions that establish the crystalline band structures no longer limit the properties of electronic materials, but they can be modified on demand by light.
Prof. Hrvoje Petek is the RK Mellon Chair Professor at the University of Pittsburgh. He received his B.S. in 1980 at Massachusetts Institute of Technology, and Ph.D. in 1985 at University of California, Berkeley. In 2000, he became a Professor of Physics, and later Professor of Chemistry, at the University of Pittsburgh. He was elected as a Fellow of the American Physical Society in 2003. In 2014, he was appointed as the Richard King Mellon Chair Professor of Physics and Astronomy, the most prestigious professor Chair at the University. In 2016, he was elected as a fellow of American Association for the Advancement of Science. In 2019, he was awarded with the Ahmed Zewail Award in Ultrafast Science and Technology of the American Chemical Society, the most important award in the field of ultrafast dynamics. He is visiting as the Luo Jia Chair Visiting Chair at Wuhan University. Dr. Petek’s research interests focus on nonequilibrium electronic phenomena at surfaces, interfaces and in solids; ultrafast plasmonics in metallic nanostructures; ultrafast microscopy of coherent excitations in solids; and surface femtochemistry and photocatalysis. He is a pioneer in the coherent ultrafast spectroscopy and microscopy of solid-state materials. From 2006, he has been the Editor-in-Chief of Progress in Surface Science.