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1. Parametric dependence of hot electron relaxation timescales on electron-electron and electron-phonon interaction strengths

   https://doi.org/10.1038/s42005-020-00442-x  

   Wilson, Richard B.; Coh, Sinisa (December 2020, Communications Physics)

   null (Ed.)

   Abstract Understanding how photoexcited electron dynamics depend on electron-electron (e-e) and electron-phonon (e-p) interaction strengths is important for many fields, e.g. ultrafast magnetism, photocatalysis, plasmonics, and others. Here, we report simple expressions that capture the interplay of e-e and e-p interactions on electron distribution relaxation times. We observe a dependence of the dynamics on e-e and e-p interaction strengths that is universal to most metals and is also counterintuitive. While only e-p interactions reduce the total energy stored by excited electrons, the time for energy to leave the electronic subsystem also depends on e-e interaction strengths because e-e interactions increase the number of electrons emitting phonons. The effect of e-e interactions on energy-relaxation is largest in metals with strong e-p interactions. Finally, the time high energy electron states remain occupied depends only on the strength of e-e interactions, even if e-p scattering rates are much greater than e-e scattering rates. 

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2. Role of electron-electron collisions for magnetotransport at intermediate temperatures

   https://doi.org/10.1103/PhysRevB.102.245117  

   Lee, Woo-Ram; Finkel'stein, Alexander M.; Schwiete, Georg (December 2020, Physical Review B)

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3. Local signatures of electron-electron scattering in an electronic cavity

   https://doi.org/10.1103/PhysRevResearch.3.013287  

   Gold, Carolin; Bräm, Beat A.; Steinacher, Richard; Krähenmann, Tobias; Hofmann, Andrea; Reichl, Christian; Wegscheider, Werner; Shayegan, Mansour; Ensslin, Klaus; Ihn, Thomas (March 2021, Physical Review Research)

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4. Nonlinear Effects of Electron‐Electron Collisions on ISR Temperature Measurements

   https://doi.org/10.1029/2019JA026753  

   Longley, William J.; Oppenheim, Meers M.; Dimant, Yakov S. (July 2019, Journal of Geophysical Research: Space Physics)

   Abstract Incoherent scatter radars (ISR) estimate the electron and ion temperatures in the ionosphere by fitting measured spectra of ion‐acoustic waves to forward models. For radars looking at aspect angles within 5° off perpendicular to the Earth's magnetic field, the magnetic field constrains electron movement and Coulomb collisions add an additional source of damping that narrows the spectra. Fitting the collisionally narrowed spectra to collisionless forward models leads to errors or underestimates of the plasma temperatures. This paper presents the first fully kinetic particle‐in‐cell (PIC) simulations of ISR spectra with collisional damping by velocity‐dependent electron‐electron and electron‐ion collisions. For aspect angles between 0.5° and 2° off perpendicular, the damping effects of electron‐ion and electron‐electron collisions in the PIC simulations are the same and the resulting spectra are narrower than what current theories and models predict. For aspect angles larger than 3° away from perpendicular, the simulations with electron‐ion collisions match collisionless ISR theory well, but spectra with electron‐electron collisions are narrower than theory predicts at aspect angles as large as 5° away from perpendicular. At aspect angles less than 5° the PIC simulations produce narrower spectra than previous simulations using single‐particle displacement statistics that include both electron‐ion and electron‐electron collisions. The narrowing of spectra by electron‐electron collisions in the PIC code between 3° and 5° away from perpendicular is currently neglected when fitting measured spectra from the Jicamarca and Millstone Hill radars, leading to underestimates of electron temperatures by as much as 25% at small aspect angles. 

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5. Controlling One-Electron vs Two-Electron Pathways in the Multi-Electron Redox Cycle of Nickel Diethyldithiocarbamate

   https://doi.org/10.1021/acs.inorgchem.1c01699  

   Mazumder, Md. Motiur; Burton, Andricus; Richburg, Chase S.; Saha, Soumen; Cronin, Bryan; Duin, Evert; Farnum, Byron H. (September 2021, Inorganic Chemistry)