In polarizable materials, electronic charge carriers interact with the surrounding ions, leading to quasiparticle behavior. The resulting polarons play a central role in many materials properties including electrical transport, interaction with light, surface reactivity, and magnetoresistance, and polarons are typically investigated indirectly through these macroscopic characteristics. Here, noncontact atomic force microscopy (nc-AFM) is used to directly image polarons in Fe2O3 at the single quasiparticle limit. A combination of Kelvin probe force microscopy (KPFM) and kinetic Monte Carlo (KMC) simulations shows that the mobility of electron polarons can be markedly increased by Ti doping. Density functional theory (DFT) calculations indicate that a transition from polaronic to metastable free-carrier states can play a key role in migration of electron polarons. In contrast, hole polarons are significantly less mobile, and their hopping is hampered further by trapping centers.

• Publikační typ
• časopisecké články MeSH

Particles of DeltaProCANC, a fusion of capsid (CA) and nucleocapsid (NC) protein of Mason-Pfizer monkey virus (M-PMV), which lacks the amino terminal proline, were reassembled in vitro and visualized by atomic force microscopy (AFM). The particles, of 83-84 nm diameter, exhibited ordered domains based on trigonal arrays of prominent rings with center to center distances of 8.7 nm. Imperfect closure of the lattice on the spherical surface was affected by formation of discontinuities. The lattice is consistent only with plane group p3 where one molecule is shared between contiguous rings. There are no pentameric clusters nor evidence that the particles are icosahedral. Tubular structures were also reassembled, in vitro, from two HIV fusion proteins, DeltaProCANC and CANC. The tubes were uniform in diameter, 40 nm, but varied in length to a maximum of 600 nm. They exhibited left handed helical symmetry based on a p6 hexagonal net. The organization of HIV fusion proteins in the tubes is significantly different than for the protein units in the particles of M-PMV DeltaProCANC.

• MeSH
• HIV * ultrastruktura   MeSH
• lidé MeSH
• makromolekulární látky MeSH
• Masonův-Pfizerův opičí virus * ultrastruktura   MeSH
• mikroskopie atomárních sil MeSH
• sestavení viru MeSH
• virion * ultrastruktura   MeSH
• virové proteiny izolace a purifikace   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH