It has been argued that the 0.7 anomaly in quantum point contacts (QPCs) isdue to an enhanced density of states at the top of the QPC-barrier (van Hoveridge), which strongly enhances the effects of interactions. Here, we analyzetheir effect on dynamical quantities. We find that they pin the van Hove ridgeto the chemical potential when the QPC is subopen; cause a temperaturedependence for the linear conductance that qualitatively agrees withexperiment; strongly enhance the magnitude of the dynamical spinsusceptibility; and significantly lengthen the QPC traversal time. We concludethat electrons traverse the QPC via a slowly fluctuating spin structure offinite spatial extent.
展开▼
