5 research outputs found
Spin fluctuations in the 0.7-anomaly in quantum point contacts
It has been argued that the 0.7 anomaly in quantum point contacts (QPCs) is
due to an enhanced density of states at the top of the QPC-barrier (van Hove
ridge), which strongly enhances the effects of interactions. Here, we analyze
their effect on dynamical quantities. We find that they pin the van Hove ridge
to the chemical potential when the QPC is subopen; cause a temperature
dependence for the linear conductance that qualitatively agrees with
experiment; strongly enhance the magnitude of the dynamical spin
susceptibility; and significantly lengthen the QPC traversal time. We conclude
that electrons traverse the QPC via a slowly fluctuating spin structure of
finite spatial extent