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1.
Transport through a double barrier in Large Radius Carbon Nanotubes
with a transverse magnetic field
S. Bellucci P. Onorato 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(4):469-476
We discuss the Luttinger Liquid behaviour of Large Radius Carbon Nanotube e.g. the Multi Wall ones (MWNT), under the action
of a transverse magnetic field B. Our results imply a reduction with B in the value of the bulk critical exponent, αbulk, for the tunneling density of states, which is in agreement with that observed in transport experiments. Then, the problem
of transport through a Quantum Dot formed by two intramolecular tunneling barriers along the MWNT, weakly coupled to Tomonaga-Luttinger
liquids is studied, including the
action of a strong transverse magnetic field B. We predict the presence of some peaks in the conductance G versus B, related
to the magnetic flux quantization in the ballistic regime, at a very low temperature T, and also at higher values of T, where
the Luttinger
behaviour dominates. The temperature dependence of the maximum Gmax of the conductance peak according to the Sequential Tunneling follows a power law, G ∝Tγe-1 with
γe linearly dependent on the critical exponent,
αend, strongly reduced by B. 相似文献
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4.
We consider the conductance of a one-dimensional wire interrupted by a double-barrier structure allowing for a resonant level. Using the electron-electron interaction strength as a small parameter, we are able to build a nonperturbative analytical theory of the conductance valid in a broad region of temperatures and for a variety of the barrier parameters. We find that the conductance may have a nonmonotonic crossover dependence on temperature, specific for a resonant tunneling in an interacting electron system. 相似文献
5.
Godfrey Gumbs 《Solid State Communications》2003,128(12):443-448
A model calculation is reported for the tunneling probability of one as well as two interacting electrons from a quantum well within a narrow channel. We discuss the cases when the two electrons are spin polarized or unpolarized by transforming the system to a noninteracting one with the use of quantal density functional theory to obtain an effective single-particle confining potential. A semiclassical approach is used to obtain the tunneling probability from this effective potential. The calculation is motivated by recent measurements of the conductance of an electron gas in a narrow channel but is not meant to explain the anomalous behavior that has been reported since, for example, we deal with a simplified two-level system. Numerical results for the tunneling probability are presented. 相似文献
6.
We analyze inelastic cotunneling through an interacting quantum dot subject to an ambient magnetic field in the weak tunneling regime under a non-adiabatic time-dependent bias-voltage. Our results clearly exhibit photon-assisted satellites and an overall suppression of differential conductance with increasing driving amplitude, which is consistent with experiments. We also predict a zero-anomaly in differential conductance under an appropriate driving frequency. 相似文献
7.
《Physics letters. A》2002,294(2):108-112
We study the dynamics of two interacting electrons confined in a double quantum dot in the presence of radiation pulses. We show that the strong transition between two localized states is induced at the avoided crossing between the corresponding energy levels, leading to the maximally entangled Bell states. The frequency and duration of selective light pulses for producing maximally entangled states are identified by both analytic and exact numerical solution of the quantum dynamical equations. 相似文献
8.
We theoretically analyze the tunneling of electrons through a heterostructure with two barriers and a quantum well between them in a magnetic field perpendicular to the current. We take into account the contribution from electrons with various positions of the magnetic oscillator center to the current. The region of the Z-shaped current-voltage characteristic for the heterostructure is shown to narrow as the magnetic field strengthens. Our analysis reveals a critical magnetic field strength at which the Z-shaped current-voltage characteristic transforms into an N-shaped one. We compare our results with experimental data. 相似文献
9.
S. I. Bozhko 《JETP Letters》2014,99(8):487-495
The foundations of the focusing of electrons by a transverse magnetic field proposed by V.S. Tsoi in 1974 have been reviewed. The kinetics of electrons in condensed media and interactions of conduction electrons with interfaces has been studied by means of the focusing of electrons. Various applications of the focusing of charge carriers in low-dimensional, including two-dimensional, electron systems have been demonstrated. 相似文献
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11.
We study the case where two interacting electrons in a double quantum dot structure are driven resonantly by a pulsed electromagnetic field and present a method that is based on controlled rotation for the creation of maximally entangled two-electron states. 相似文献
12.
Accurate auxiliary field quantum Monte-Carlo (AFQMC) simulations of interacting electrons in quantum dots are reported. Two different formulations of this approach are presented both of which have been designed specifically for application to quantum dots. A deflation technique for calculation of anti-symmetrized traces is introduced. The auxiliary field is sampled with a hybrid algorithm and the artificial dynamics needed for use with the present formulation of AFQMC is described. The constrained path approximation is used to control the sign problem. Results for the ground state energy of two spin-polarised, interacting electrons are presented and are found to agree well with exact diagonalization results for a wide range of screening lengths. The sign problem does not appear in the regime of small screening length. 相似文献
13.
A. Gharaati 《Superlattices and Microstructures》2012,51(1):194-202
In this paper, we study the electron effective Landé g-factor in the InAs quantum wire under an applied magnetic field and the Rashba effect. For this goal, we first present an analytic solution to one-particle Schrödinger equation in the presence of both magnetic field and spin-orbit interaction (SOI). Then, using the obtained energy levels, we study the electron effective Landé g-factor. It is found that: (i) The effective Landé g-factor decreases when magnetic field increases. (ii) By increasing the confinement length l0, the electron g-factor decreases. (iii) By increasing the strength of SOI, the electron g-factor increases. 相似文献
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Nonequilibrium spin transport through an interacting quantum dot is analyzed. The coherent spin oscillations in the dot provide a generating source for spin current. In the interacting regime, the Kondo effect is influenced in a significant way by the presence of the processing magnetic field. In particular, when the precession frequency is tuned to resonance between spin-up and spin-down states of the dot, Kondo singularity for each spin splits into a superposition of two resonance peaks. The Kondo-type cotunneling contribution is manifested by a large enhancement of the pumped spin current in the strong coupling low temperature regime. 相似文献
17.
V. A. Geiler V. A. Margulis L. I. Filina 《Journal of Experimental and Theoretical Physics》1998,86(4):751-762
We examine the ballistic conductance of a quantum wire in a parallel magnetic field in the presence of several impurities
and derive analytic expressions for the transmission coefficient and the conductance in such a system. We show that scattering
by impurities leads to a number of sharp peaks near the thresholds of the conductance quantization steps. The number of such
peaks is determined by the distance between the impurities and the energy of the scattered particle. We also study the conductivity
of a quantum wire in the region where the transport mechanism is diffusive. The conductivity is examined for the case in which
charge carriers are scattered by randomly distributed point impurities. We study Shubnikov-de Haas oscillations in such a
system. The general oscillation pattern consists of broad minima separated by irregularly spaced sharp peaks of the burst
type.
Zh. éksp. Teor. Fiz. 113, 1376–1396 (April 1998) 相似文献
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19.
M. Motamedifar S. Mahdavifar S. Farjami Shayesteh 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,83(2):181-189
We study the magnetic behaviors of a spin-1/2 quantum compass chain (QCC) in a transverse magnetic field, by means of the
analytical spinless fermion approach and numerical Lanczos method. In the absence of the magnetic field, the phase diagram
is divided into four gapped regions. To determine what happens by applying a transverse magnetic field, using the spinless
fermion approach, critical fields are obtained as a function of exchanges. Our analytical results show, the field-induced
effects depend on in
which one of the four regions the system is. In two regions of the phase diagram, the Ising-type phase transition happens
in a finite field. In another region, we have identified two quantum phase transitions (QPT)s in the ground state magnetic
phase diagram. These quantum phase transitions belong to the universality class of the commensurate-incommensurate phase transition.
We also present a detailed numerical analysis of the low energy spectrum and the ground state magnetic phase diagram. In particular,
we show that the intermediate state (h
c1 < h < h
c2) is gapful, describing the spin-flop phase. 相似文献
20.
We consider scattering of a nonrelativistic quantum particle by a one-dimensional fractal potential barrier carried by a generalized Cantor set. We obtain recurrence relations for the reflection coefficient and examine the scaling properties as functions of the wave number.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 120–127, July, 1993. 相似文献