The exploitation of the spin in charge-based systems is opening revolutionary opportunities for device architecture. Surprisingly, room temperature electrical transport through magnetic nanowires is still an unresolved issue. Here, we show that ferromagnetic (Co) suspended atom chains spontaneously display an electron transport of half a conductance quantum, as expected for a fully polarized conduction channel. Similar behavior has been observed for Pd (a quasimagnetic $4d$ metal) and Pt (a nonmagnetic $5d$ metal). These results suggest that the nanowire low dimensionality reinforces or induces magnetic behavior, lifting off spin degeneracy even at room temperature and zero external magnetic field.

We have analyzed the atomic arrangements and quantum conductance of silver nanowires generated by mechanical elongation. The surface properties of Ag induce unexpected structural properties, such as, for example, predominance of high aspect-ratio rodlike wires. The structural behavior was used to understand the Ag quantum conductance data and the proposed correlation was confirmed by means of theoretical calculations. These results emphasize that the conductance of metal point contacts is determined by the preferred atomic structures, and that atomistic descriptions are essential to interpret the quantum transport behavior of metal nanostructures.

Lead halide perovskites have emerged as promising materials for light-emitting devices. Here, we report the preparation of colloidal CsPbBr₃ nanoplatelets (3 × 4 × 23 nm³) experiencing a strong quasi-one-dimensional quantum confinement. Ultrafast transient absorption and broadband fluorescence up-conversion spectroscopies were employed to scrutinize the carrier and quasiparticle dynamics and to obtain a full description of the spectroscopic properties of the material. An exciton binding energy of 350 meV, an absorption cross section at 3.2 eV of 5.0 ± 0.3 × 10^–15 cm^–2, an efficient biexciton Auger recombination lifetime of 9 ± 1 ps, and a biexciton binding energy of 74 ± 4 meV were determined. Moreover, a short-lived emission from hot excitons was observed, which is related to the formation of band-edge excitons. The time constant of both processes is 300 ± 50 fs. These results show that CsPbBr₃ nanoplatelets are indeed quite promising for light-emitting technological applications.

We present a study of the structural and quantum conductance properties of atomic-size copper nanowires generated by mechanical stretching. The atomistic evolution was derived from time-resolved electron microscopy observations and molecular dynamics simulations. We have analyzed the quantum transport behavior by means of conductance measurements and theoretical calculations. The results suggest the formation of an unusual and highly stable pentagonal Cu nanowire with a diameter of $\sim 0.45\mathrm{n}\mathrm{m}$ and $\sim 4.5$ conductance quanta.