SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Building upon our experience in studying the influences of geometric phase and interaction effects on electronic properties, we have performed theoretical research on the manipulation of magnetic and excitonic degrees of freedom in some two-dimensional and quasi two-dimensional systems.
Low-frequency magnetoplasmon modes in a one-dimensional lateral superlattice with Rashba spin-orbit splitting are considered. Such modes correspond to oscillations related to virtual transitions within a Landau level that become possible due to the broadening of each Landau level into a band produced by the superlattice potential. The specificity of the one-dimensional intersubband plasmons emerging in such a system has been revealed.
None provided.
Abstract Real-time probing of electrons can uncover intricate relaxation mechanisms and many-body interactions in strongly correlated materials. Here, we introduce time, momentum, and energy resolved pump-probe tunneling spectroscopy (Tr-MERTS). The method allows the injection of electrons at a particular energy and observation of their subsequent decay in energy-momentum space. Using Tr-MERTS, we visualize electronic decay processes, with lifetimes from tens of nanoseconds to tens of microseconds, in Landau levels formed in a GaAs quantum well. Although most observed features agree with simple energy-relaxation, we discovered a splitting in the nonequilibrium energy spectrum in the vicinity of a ferromagnetic state. An exact diagonalization study suggests that the splitting arises from a maximally spin-polarized state with higher energy than a conventional equilibrium skyrmion. Furthermore, we observe time-dependent relaxation of the splitting, which we attribute to single-flipped spins forming skyrmions. These results establish Tr-MERTS as a powerful tool for studying the properties of a 2DES beyond equilibrium.
No abstract prepared.
Not Available
Not Available
Not Available
Here, we find a giant inverse proximity effect that arises in small low-dimensional superconductor-normal-superconductor (S/N/S) junctions, where a proximity coherence length is larger than the coherence length of a source superconductor, due to a huge backaction exerted by normal conductors on the proximity superconducting regions. Furthermore, the inverse proximity develops even in case where dimensions of the normal parts are smaller than the proximity coherence length and significantly suppresses superconducting characteristics of the entire system, including critical current, well below those for the usual S/N/S structures.
Not Available
Abstract not provided.