ORCID Profile
0000-0001-5055-3330
Current Organisation
Victoria University of Wellington
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Publisher: American Physical Society (APS)
Date: 21-01-2010
Publisher: American Physical Society (APS)
Date: 03-12-2014
Publisher: American Physical Society (APS)
Date: 11-07-2006
Publisher: AIP Publishing
Date: 11-04-2011
DOI: 10.1063/1.3579197
Abstract: We present a theoretical study of ac charge transport arising from adiabatic temporal variation of zero-field spin splitting in a quasi-one-dimensional hole system (realized, e.g., in a quantum wire or point contact). As in conduction-electron systems, part of the current results from spin-dependent electromotive forces. We find that the magnitude of this current contribution is two orders of magnitude larger for holes and exhibits parametric dependences that make it more easily accessible experimentally. Our results suggest hole structures to be good candidates for realizing devices where spin currents are pumped by time-varying electric fields.
Publisher: IOP Publishing
Date: 23-09-2009
DOI: 10.1088/0953-8984/21/41/415302
Abstract: We present a theory for spin-polarized transport through a generic organic polymer connected to ferromagnetic leads with arbitrary angle θ between their magnetization directions, taking into account the polaron and bipolaron states as effective charge and spin carriers. Within a diffusive description of polaron-bipolaron transport including polaron-bipolaron conversion, we find that the bipolaron density depends on the angle θ. This is remarkable, given the fact that bipolarons are spinless quasiparticles, and opens a new way to probe spin accumulation in organic polymers.
Publisher: IOP Publishing
Date: 24-03-2010
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2730082
Publisher: IOP Publishing
Date: 22-08-2011
DOI: 10.1088/0953-8984/23/36/362201
Abstract: The semiconductor quantum point contact has long been a focal point for studies of one-dimensional (1D) electron transport. Their electrical properties are typically studied using ac conductance methods, but recent work has shown that the dc conductance can be used to obtain additional information, with a density-dependent Landé effective g-factor recently reported (Chen et al 2009 Phys. Rev. B 79 081301). We discuss previous dc conductance measurements of quantum point contacts, demonstrating how valuable additional information can be extracted from the data. We provide a comprehensive and general framework for dc conductance measurements that provides a path to improving the accuracy of existing data and obtaining useful additional data. A key aspect is that dc conductance measurements can be used to map the energy of the 1D sub-band edges directly, giving new insight into the physics that takes place as the spin-split 1D sub-bands populate. Through a re-analysis of the data obtained by Chen et al, we obtain two findings. The first is that the 2↓ sub-band edge closely tracks the source chemical potential when it first begins populating before dropping more rapidly in energy. The second is that the 2↑ sub-band populates more rapidly as the sub-band edge approaches the drain potential. This second finding suggests that the spin-gap may stop opening, or even begin to close again, as the 2↑ sub-band continues populating, consistent with recent theoretical calculations and experimental studies.
No related grants have been discovered for Ulrich Zuelicke.