Plenary and Semi-Plenary Speakers
PLENARY SPEAKERS
Mesoscopic electrodynamics, nonlocal response, and quantum corrections in surface-polariton systems
The electrodynamics of matter and optical phenomena are commonly explored within the framework of classical electrodynamics and semiclassical models for the interactions of light with matter. Materials are commonly assumed homogenous, and light-matter interactions are treated in an intuitive local manner. The plasmon-polaritons response of conductive materials is one such example, where the understanding of mesoscopic electrodynamics is, however, becoming increasingly important for both fundamental developments in quantum plasmonics and potential applications in emerging lightbased quantum technologies. The plenary talk will discuss recent examples of nonlocal effects and quantum corrections that emerge in surface-polaritonic systems, including metal surfaces, 2D materials, and combinations thereof.
Eva Andrei
Rutgers University, United States
Structural and electronic coupling at oxide interfaces
In this talk, I will discuss several interfacial couplings that can occur in oxide heterostructures. Polar discontinuities, for instance, can lead to 2-dimensional conduction between insulating materials and I will briefly discuss the case of the LaAlO3/SrTiO3 system. Structural and electronic coupling at oxide interfaces can also lead to interesting phenomena that we investigated in perovskite nickelates - well-known for their metal to insulator transition (MIT) and unique antiferromagnetic (AFM) ground state. There, I will show that there in an interfacial phase boundary cost between metallic and insulating regions that can be used to couple MIT’s or to turn a metal into an insulator. Finally I will present results on vanadatebased heterostructures where oxygen octahedra rotation coupling at orthorhombic interfaces leads to an “intermediate layer” that allows the orthorhombic structure to reorient its long-axis – a layer in unique strain conditions - that could become functional.
SEMI-PLENARY SPEAKERS
Joaquín Fernández-Rossier
INL, Braga, Portugal
Flat bands, entanglement and fractionalization in bottom-up quantum matter
In this talk I will discuss two key problems in modern condensed matter physics. First, how to design artificial quantum matter endowed with non-trivial emergent properties such as flat-bands, entanglement and fractionalization, through the assembly of simpler building blocks such as nanographenes. Specifically, I will present the fascinating properties of spin-chains that have been already realized experimentally, such as the Haldane S=1 spin chain and the alternate exchange S=1/2 chain, as well as our predictions for nanographene two-dimensional crystals. Second, I will discuss how to probe the resulting emergent properties in these fascinating systems using scanning probes. In particular, I will show two techniques based on scanning tunnel microscopy (STM), inelastic electron tunnel spectroscopy (IETS-STM) and electron spin resonance (ESR-STM), provide information about the spin excitations, quantum entanglement and fractionalization in these structures. Finally will touch upon future prospects aimed at dynamically manipulating the quantum states in this class of artificial quantum materials.
Mário Silveirinha
Instituto Superior Técnico, Lisboa, Portugal
Distributed transistor response with chiral gain
Semiconductor transistors are key elements of electronic circuits as they enable, for example, the isolation and amplification of voltage signals. While conventional transistors are point-type devices, it would be highly interesting to realize a distributed transistor-type optical response in a bulk material.
In this talk, I will present an overview of the work of my group on distributed transistor- metamaterials. I will show that the interplay of static electric bias and material nonlinearities may enable the design of non-Hermitian and non-reciprocal transistor-like metamaterial responses. Moreover, it will be shown that natural low-symmetry materials may be the ideal platforms to implement such a distributed-transistor response.
I will introduce a novel non-Hermitian electro-optic effect controlled by the Berry curvature dipole of a material. Under a static electric bias, the electro-optic effect alters the optical conductivity of the material, breaking electromagnetic reciprocity and yielding a dynamic non-Hermitian response similar to a transistor but distributed throughout the volume. Notably, the active or dissipative nature of the material response is dependent on the handedness of the electromagnetic wave. For waves polarized to the right, the response may be active (with optical gain), while the opposite handedness results in a dissipative response. I will outline several exciting applications for transistor metamaterials and discuss how this class of metamaterials has the potential to usher in a new era of terahertz devices that are both active and nonreciprocal.
Franca Albertini
IMEM-CNR, Parma, Italy
Christiane Smith
Utrecht University, The Netherlands
Andreas Wallraff
ETH Zürich, Switzerland
Claire Donnelly
Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
Pascale Launois
University Paris-Saclay, France
The amazing properties of nano-confined water
A groundbreaking discovery in nanofluidics was the observation of the tremendously enhanced water permeability of carbon nanotubes, at the origin of an intensive research activity. Original experimental devices have been developed to measure flow through an individual nano-channel. In contrast to this "nano" approach, "macroscopic" approaches, i.e. studies of the properties of nano-confined fluids over billions of billions of nano-channels, provide additional and complementary information.
The original phase diagram of nanoconfined water, amazing structuration of water, its peculiar hydrogen bonding network, its specific vibrational and diffusion properties will be discussed based on the literature and on our studies.
Two different types of one-dimensional nanocontainers, respectively hydrophobic and hydrophilic, are considered: single-walled carbon nanotubes and single-walled imogolite nanotubes of nominal composition SiAl2O7H4 and GeAl2O7H4, with different diameters. We will present the results of a multi-technique approach, combining X-ray scattering, quasi-elastic and inelastic neutron scattering, infra-red spectroscopy and molecular dynamics simulations. We will also show that a flux measurement through an individual imogolite nanotube would lead to incorrect flux value.
Markus Munzenberg
Greifswald University, Germany
Ultrafast spintronics on attosecond time scales
Magnetization manipulation is an indispensable tool for both basic and applied research. I will discuss an actual overview on ultrafast magnetism and THz spintronics. The dynamics of the spin response depends on the energy transfer from the laser excited electrons to the spins within the first femtoseconds. Due to the non-equilibrium electron distribution in layered nanoscale spintronic devices, ultrafast spin currents are generated and contribute to the laser driven spin dynamics. Ultrafast laser-driven spin currents can be converted via the spin-Hall effect into a charge current burst that can even compete with state-of-art THz emitters. They allow to map topological spin structures, and their THz dynamics, with potentially with sub micron resolution as we recently demonstrated. We have also recently shown that attosecond lasers are breaking new frontiers and records towards the observation of coherent spin processes on ever shorter time scales, reaching Petaherz light frequency spintronics. Using light wave coherent charge transfer, driven by a few cycle laser pulse, I will report the first coherent attosecond magnetism in layered spintronic devices. These experiments, the fastest spin-dynamics observed experimentally, fit perfectly to the time scales for time resolved DFT, from theoretical sides revealing a coherent electron transfer at interfaces in operado. This opens up applications of coherent spin current processes.
Andrea Cavalleri
Max Planck Institute, Hamburg, Germany