Real-time observation of non-equilibrium phonon-electron energy and angular momentum flow in laser-heated nickel.
Vishal ShokeenMichael HeberDmytro KutnyakhovXiaocui WangAlexander A YaroslavtsevPablo MaldonadoMarco BerrittaNils O WindLukas WenthausFederico PressaccoChul-Hee MinMatz NissenSanjoy Kr MahathaSiarhei DziarzhytskiPeter M OppeneerKai RossnagelHans-Joachim ElmersGerd SchönhenseHermann A DürrPublished in: Science advances (2024)
Identifying the microscopic nature of non-equilibrium energy transfer mechanisms among electronic, spin, and lattice degrees of freedom is central to understanding ultrafast phenomena such as manipulating magnetism on the femtosecond timescale. Here, we use time- and angle-resolved photoemission spectroscopy to go beyond the often-used ensemble-averaged view of non-equilibrium dynamics in terms of quasiparticle temperature evolutions. We show for ferromagnetic Ni that the non-equilibrium electron and spin dynamics display pronounced variations with electron momentum, whereas the magnetic exchange interaction remains isotropic. This highlights the influence of lattice-mediated scattering processes and opens a pathway toward unraveling the still elusive microscopic mechanism of spin-lattice angular momentum transfer.
Keyphrases
- molecular dynamics
- energy transfer
- density functional theory
- room temperature
- molecular dynamics simulations
- single molecule
- electron transfer
- transition metal
- high resolution
- aqueous solution
- solar cells
- quantum dots
- electron microscopy
- gold nanoparticles
- ionic liquid
- convolutional neural network
- deep learning
- metal organic framework
- reduced graphene oxide
- solid state