2011/11/21 by Chien-Liang Chen, Chien‐Liang Chen, Ching‐Ray Chang +3 · 14 citations
Materials Science · Physics and Astronomy · #Coherence (philosophical gambling strategy) #Coherence length #Condensed matter physics #Dephasing #Dirac (video compression format) #Electron #Graphene #Graphene research and applications #Magnetic field #Magnetoresistance #Physics #Quantum #Quantum Hall effect #Quantum and electron transport phenomena #Quantum entanglement #Quantum mechanics #Quantum nonlocality #Spin (aerodynamics) #Spin Hall effect #Spin polarization #Superconductivity #Topological Materials and Phenomena #Weak localization #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.85.155414
published in Physical Review B 85(15) (American Physical Society) · 5 pages, 4 figures, PDFLaTeX
arxiv created 2011/11/21 · openalex publication_date 2012/04/09 · arxiv updated 2012/04/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Motivated by the recent experimental observation [Abanin et al., Science 332, 328 (2011)] of nonlocality in magnetotransport near the Dirac point in six-terminal graphene Hall bars, for a wide range of temperatures and magnetic fields, we develop a nonequilibrium Green's function theory of this phenomenon. In the quantum-coherent regime and strong magnetic field, we find large Zeeman-splitting-driven spin Hall (SH) conductance in four-terminal bars, where the SH current is pure only at the Dirac point (DP). In six-terminal Hall bars, this leads to the nonlocal voltage at a remote location due to direct and inverse SH effect operating at the same time in different parts of the device. The ``momentum-relaxing'' dephasing reduces their values at the DP by two orders of magnitude while concurrently washing out any features away from the DP. Our theory is based on the Meir-Wingreen formula for spin-resolved charge currents with dephasing introduced via phenomenological many-body self-energies, which is then linearized for multiterminal geometries to extract currents and voltages. This provides a generalization of the multiprobe Landauer-B"uttiker formula without employing traditional B"uttiker voltage probes to introduce dephasing.