اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدNegative differential conductance induced by electronic correlation in a double quantum-dot molecule
415
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Electron tunneling through a two stage Kondo system constituted by a double quantum-dot molecule side coupled to a quantum wire, under the effect of a finite external potential is studied. We found that $I$-$V$ characteristic shows a negative differential conductance region induced by the electronic correlation. This phenomenon is a consequence of the properties of the two stage Kondo regime under the effect of an external applied potential that takes the system out of equilibrium. The problem is solved using the mean-field finite-$U$ slave-boson formalism.
قيم البحث
اقرأ أيضاً
We report a bi-polar multiple periodic negative differential conductance (NDC) effect on a single cage-shaped Ru nanoparticle measured using scanning tunneling spectroscopy. This phenomenon is assigned to the unique multiply-connected cage architectu
re providing two (or more) defined routes for charge flow through the cage. This, in turn, promotes a self- gating effect, where electron charging of one route affects charge transport along a neighboring channel, yielding a series of periodic NDC peaks. This picture is established and analyzed here by a theoretical model.
The large, level-dependent g-factors in an InSb nanowire quantum dot allow for the occurrence of a variety of level crossings in the dot. While we observe the standard conductance enhancement in the Coulomb blockade region for aligned levels with dif
ferent spins due to the Kondo effect, a vanishing of the conductance is found at the alignment of levels with equal spins. This conductance suppression appears as a canyon cutting through the web of direct tunneling lines and an enclosed Coulomb blockade region. In the center of the Coulomb blockade region, we observe the predicted correlation-induced resonance, which now turns out to be part of a larger scenario. Our findings are supported by numerical and analytical calculations.
We study transport of non-interacting electrons through two quantum dot molecules embedded in an Aharonov-Bohm interferometer. The system in equilibrium exhibits bound states in the continuum (BIC) and total suppression of transmission. It also shows
a magnetic flux-dependent effective level attraction and lines of perfect transmission when the intramolecular coupling is weak. Out of equilibrium, the current displays two kind of negative differential conductance (NDC) regions, which have different origins. One is generated by the usual mechanism of the NDC arising in a double quantum dot system. The other is induced by the magnetic flux, and it occurs at small voltages and for a well definite range of the intramolecular couplings. We explain this effect in terms of the level attraction displayed by the system.
The zero-temperature conductance of diatomic molecule, modelled as a correlated double quantum dot attached to noninteracting leads is investigated. We utilize the Rejec-Ramsak formulas, relating the linear-response conductance to the ground-state en
ergy dependence on magnetic flux within the framework of EDABI method, which combines exact diagonalization with ab initio calculations. The single-particle basis renormalization leads to a strong particle-hole asymmetry, of the conductance spectrum, absent in a standard parametrized model study. We also show, that the coupling to leads V=0.5t (t is the hopping integral) may provide the possibility for interatomic distance manipulation due to the molecule instability.
The slowdown of optical pulses due to quantum-coherence effects is investigated theoretically for an active material consisting of InGaAs-based double quantum-dot molecules. These are designed to exhibit a long lived coherence between two electronic
levels, which is an essential part of a quantum coherence scheme that makes use of electromagnetically-induced transparency effects to achieve group velocity slowdown. We apply a many-particle approach based on realistic semiconductor parameters that allows us to calculate the quantum-dot material dynamics including microscopic carrier scattering and polarisation dephasing dynamics. The group-velocity reduction is characterized in the frequency domain by a quasi-equilibrium slow-down factor and in the time domain by the probe-pulse slowdown obtained from a calculation of the spatio-temporal material dynamics coupled to the propagating optical field. The group-velocity slowdown in the quantum-dot molecule is shown to be substantially higher than what is achievable from similar transitions in typical InGaAs-based single quantum dots. The dependences of slowdown and shape of the propagating probe pulses on lattice temperature and drive intensities are investigated.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
