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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi
Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
We consider the current induced in a quantum wire by external electromagnetic radiation. The photocurrent is caused by the interplay of spin-orbit interaction (Rashba and Dresselhaus terms) and an external in-plane magnetic field. We calculate this current using a Wigner functions approach, taking into account radiation-induced transitions between transverse subbands. The magnitude and the direction of the current depends on the Dresselhaus and Rashba constants, strength of magnetic field, radiation frequency, and intensity. The current can be controlled by changing some of these parameters.
Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
We analyze theoretically the dynamics of N electrons localized in a narrow semiconductor quantum ring under a train of phase-locked infrared laser pulses. The pulse sequence is designed to control the total angular momentum of the electrons. The quantum ring can be put in states characterized by strong currents. The local magnetic field created by these currents can be used for a selective quantum control of single spins in semiconductor systems. The current generation in quantum rings with finite width is also studied.
Photovoltaic Effect In Bent Quantum Wires In The Ballistic Transport Regime, Yuriy V. Pershin Dr, Carlo Piermarocchi
Photovoltaic Effect In Bent Quantum Wires In The Ballistic Transport Regime, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
A scheme for the generation of a photocurrent in bent quantum wires is proposed. We calculate the current using a generalized Landauer-Büttiker approach that takes into account the electromagnetic radiation. For circularly polarized light, it is demonstrated that the curvature in the bent wire induces an asymmetry in the scattering coefficients for left and right moving electrons. This asymmetry results in a current at zero bias voltage. The effect is due to the geometry of the wire which transforms the photon angular momentum into translational motion for the electrons. Possible experimental realizations of this scheme are discussed.
Persistent And Radiation-Induced Currents In Distorted Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Persistent And Radiation-Induced Currents In Distorted Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
Persistent and radiation-induced currents in distorted narrow quantum rings are theoretically investigated. We show that ring distorsions can be described using a geometrical potential term. We analyze the effect of this term on the current induced by a magnetic flux (persistent current) and by a polarized coherent electromagnetic field (radiation-induced current). The strongest effects in persistent currents are observed for distorted rings with a small number of electrons. The distortion smoothes the current oscillations as a function of the magnetic flux and changes the temperature dependence of the current amplitude. For radiation-induced currents, the distortion induces an ac component in …
Temperature-Dependent Asymmetry Of The Nonlocal Spin-Injection Resistance: Evidence For Spin Nonconserving Interface Scattering, Samir Garzon, Igor Žutić, Richard A. Webb
Temperature-Dependent Asymmetry Of The Nonlocal Spin-Injection Resistance: Evidence For Spin Nonconserving Interface Scattering, Samir Garzon, Igor Žutić, Richard A. Webb
Faculty Publications
We report nonlocal spin injection and detection experiments on mesoscopic Co-Al2O3-Cu spin valves. We have observed a temperature-dependent asymmetry in the nonlocal resistance between parallel and antiparallel configurations of the magnetic injector and detector. This strongly supports the existence of a nonequilibrium resistance that depends on the relative orientation of the detector magnetization and the nonequilibrium magnetization in the normal metal providing evidence for increasing interface spin scattering with temperature.
Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr
Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr
Faculty Publications
We study evolution of electron spin coherence having nonhomogeneous direction of spin polarization vector in semiconductor heterostructures. It is found that the electron spin relaxation time due to the D’yakonov- Perel’ relaxation mechanism essentially depends on the initial spin polarization distribution. This effect has its origin in the coherent spin precession of electrons diffusing in the same direction. We predict a long spin relaxation time of a novel structure: a spin coherence standing wave and discuss its experimental realization.