We explore inelastic cotunneling through a strongly Coulomb-blockaded quantum dot attached to twoferromagnetic leads in the weak coupling limit using a generic quantum Langevin equation approach.We first developa B1oc...We explore inelastic cotunneling through a strongly Coulomb-blockaded quantum dot attached to twoferromagnetic leads in the weak coupling limit using a generic quantum Langevin equation approach.We first developa B1och-type equation microscopically to describe the cotunneling-induced spin relaxation dynamics,and then developexplicit analytical expressions for the local magnetization,current,and its fluctuations.On this basis,we predict a novelzero-bias anomaly of the differential conductance in the absence of a magnetic field for the anti-parallel configuration,and asymmetric peak splitting in a magnetic field.Also,for the same system with large polarization,we find a negativezero-frequency differential shot noise in the low positive bias-voltage region. All these effects are ascribed to rapidspin-reversal due to underlying spin-flip cotunneling.展开更多
We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） n...We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the Coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the Coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.展开更多
基金The project supported by National Natural Science Foundation of Chinathe Shanghai Municipal Commission of Science and Technology+2 种基金the Shanghai Pujiang Programthe Program for New Century Excellent Talents in Universities (NCET)NJMH is supported by the DURINT program administered by the US Army Research Office, DAAD Grant No. 19-O1-1-0592
文摘We explore inelastic cotunneling through a strongly Coulomb-blockaded quantum dot attached to twoferromagnetic leads in the weak coupling limit using a generic quantum Langevin equation approach.We first developa B1och-type equation microscopically to describe the cotunneling-induced spin relaxation dynamics,and then developexplicit analytical expressions for the local magnetization,current,and its fluctuations.On this basis,we predict a novelzero-bias anomaly of the differential conductance in the absence of a magnetic field for the anti-parallel configuration,and asymmetric peak splitting in a magnetic field.Also,for the same system with large polarization,we find a negativezero-frequency differential shot noise in the low positive bias-voltage region. All these effects are ascribed to rapidspin-reversal due to underlying spin-flip cotunneling.
文摘We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the Coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the Coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.
