ترغب بنشر مسار تعليمي؟ اضغط هنا

Effect of deconfinement on resonant transport in quantum wires

146   0   0.0 ( 0 )
 نشر من قبل Toni Ramsak
 تاريخ النشر 1998
  مجال البحث فيزياء
والبحث باللغة English
 تأليف A. Ramsak




اسأل ChatGPT حول البحث

The effect of deconfinement due to finite band offsets on transport through quantum wires with two constrictions is investigated. It is shown that the increase in resonance linewidth becomes increasingly important as the size is reduced and ultimately places an upper limit on the energy (temperature) scale for which resonances may be observed.



قيم البحث

اقرأ أيضاً

We develop a theory of thermal transport of weakly interacting electrons in quantum wires. Unlike higher-dimensional systems, a one-dimensional electron gas requires three-particle collisions for energy relaxation. The fastest relaxation is provided by the intrabranch scattering of comoving electrons which establishes a partially equilibrated form of the distribution function. The thermal conductance is governed by the slower interbranch processes which enable energy exchange between counterpropagating particles. We derive an analytic expression for the thermal conductance of interacting electrons valid for arbitrary relation between the wire length and electron thermalization length. We find that in sufficiently long wires the interaction-induced correction to the thermal conductance saturates to an interaction-independent value.
When a quantum wire is weakly confined, a conductance plateau appears at e^2/h with decreasing carrier density in zero magnetic field accompanied by a gradual suppression of the 2e^2/h plateau. Applying an in-plane magnetic field B|| does not alter t he value of this quantization; however, the e^2/h plateau weakens with increasing B|| up to 9 T, and then strengthens on further increasing B||, which also restores the 2e^2/h plateau. Our results are consistent with spin-incoherent transport in a one-dimensional wire.
214 - A.W. Cummings , R. Akis , 2014
We use numerical simulations to investigate the spin Hall effect in quantum wires in the presence of both Rashba and Dresselhaus spin-orbit coupling. We find that the intrinsic spin Hall effect is highly anisotropic with respect to the orientation of the wire, and that the nature of this anisotropy depends strongly on the electron density and the relative strengths of the Rashba and Dresselhaus spin-orbit coupling. In particular, at low densities when only one subband of the quantum wire is occupied, the spin Hall effect is strongest for electron momentum along the $[bar{1}10]$ axis, which is opposite than what is expected for the purely 2D case. In addition, when more than one subband is occupied, the strength and anisotropy of the spin Hall effect can vary greatly over relatively small changes in electron density, which makes it difficult to predict which wire orientation will maximize the strength of the spin Hall effect. These results help to illuminate the role of quantum confinement in spin-orbit-coupled systems, and can serve as a guide for future experimental work on the use of quantum wires for spin-Hall-based spintronic applications.
We demonstrate the emergence of the quantum Hall (QH) hierarchy in a 2D model of coupled quantum wires in a perpendicular magnetic field. At commensurate values of the magnetic field, the system can develop instabilities to appropriate inter-wire ele ctron hopping processes that drive the system into a variety of QH states. Some of the QH states are not included in the Haldane-Halperin hierarchy. In addition, we find operators allowed at any field that lead to novel crystals of Laughlin quasiparticles. We demonstrate that any QH state is the groundstate of a Hamiltonian that we explicitly construct.
Quantum conductance fluctuations are investigated in disordered 3D topological insulator quantum wires. Both experiments and theory reveal a new transport regime in a mesoscopic conductor, pseudo-ballistic transport, for which ballistic properties pe rsist beyond the transport mean free path, characteristic of diffusive transport. It results in non-universal conductance fluctuations due to quasi-1D surface modes, as observed in long and narrow Bi$_2$Se$_3$ nanoribbons. Spin helical Dirac fermions in quantum wires retain pseudo-ballistic properties over an unusually broad energy range, due to strong quantum confinement and weak momentum scattering.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا