اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدShot Noise of Single-Electron Tunneling in 1D Arrays
40
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We have used numerical modeling and a semi-analytical calculation method to find the low frequency value S_{I}(0) of the spectral density of fluctuations of current through 1D arrays of small tunnel junctions, using the ``orthodox theory of single-electron tunneling. In all three array types studied, at low temperature (kT << eV), increasing current induces a crossover from the Schottky value S_{I}(0)=2e<I> to the ``reduced Schottky value S_{I}(0)=2e<I>/N (where N is the array length) at some crossover current I_{c}. In uniform arrays over a ground plane, I_{c} is proportional to exp(-lambda N), where 1/lambda is the single-electron soliton length. In arrays without a ground plane, I_{c} decreases slowly with both N and lambda. Finally, we have calculated the statistics of I_{c} for ensembles of arrays with random background charges. The standard deviation of I_{c} from the ensemble average <I_{c}> is quite large, typically between 0.5 and 0.7 of <I_{c}>, while the dependence of <I_{c}> on N or lambda is so weak that it is hidden within the random fluctuations of the crossover current.
قيم البحث
اقرأ أيضاً
We have fabricated a custom cryogenic Complementary Metal-Oxide-Semiconductor (CMOS) integrated circuit that has a higher measurement bandwidth compared with conventional room temperature electronics. This allowed implementing single shot operations
and observe the real-time evolution of the current of a phosphorous-doped silicon single electron transistor that was irradiated with a microwave pulse. Relaxation times up to 90 us are observed, suggesting the presence of well isolated electron excitations within the device. It is expected that these are associated with long decoherence time and the device may be suitable for quantum information processing.
Usual paradigm in the theory of electron transport is related to the fact that the dielectric permittivity of the insulator is assumed to be constant, no time dispersion. We take into account the slow polarization dynamics of the dielectric layers in
the tunnel barriers in the fluctuating electric fields induced by single-electron tunneling events and study transport in the single electron transistor (SET). Here slow dielectric implies slow compared to the characteristic time scales of the SET charging-discharging effects. We show that for strong enough polarizability, such that the induced charge on the island is comparable with the elementary charge, the transport properties of the SET substantially deviate from the known results of transport theory of SET. In particular, the coulomb blockade is more pronounced at finite temperature, the conductance peaks change their shape and the current-voltage characteristics show the memory-effect (hysteresis). However, in contrast to SETs with ferroelectric tunnel junctions, here the periodicity of the conductance in the gate voltage is not broken, instead the period strongly depends on the polarizability of the gate-dielectric. We uncover the fine structure of the hysteresis-effect where the large hysteresis loop may include a number of smaller loops. Also we predict the memory effect in the current-voltage characteristics $I(V)$, with $I(V) eq -I(-V)$.
We study the behavior of shot noise in resonant tunneling junctions far from equilibrium. Quantum-coherent elastic charge transport can be characterized by a transmission function, that is the probability for an incoming electron at a given energy to
tunnel through a potential barrier. In systems such as quantum point contacts, electronic shot noise is oftentimes calculated based on a constant (energy independent) transmission probability, a good approximation at low temperatures and under a small bias voltage. Here, we generalize these investigations to far from equilibrium settings by evaluating the contributions of electronic resonances to the electronic current noise. Our study extends canonical expressions for the voltage-activated shot noise and the recently discovered delta-T noise to the far from equilibrium regime, when a high bias voltage or a temperature difference is applied. In particular, when the Fermi energy is located on the shoulder of a broad resonance, we arrive at a formula for the shot noise revealing anomalous-nonlinear behavior at high bias voltage.
Strong evidence of a single-photon tunneling effect, a direct analog of single-electron tunneling, has been obtained in the measurements of light tunneling through individual subwavelength pinholes in a thick gold film covered with a layer of polydia
cetylene. The transmission of some pinholes reached saturation because of the optical nonlinearity of polydiacetylene at a very low light intensity of a few thousands photons per second. This result is explained theoretically in terms of photon blockade, similar to the Coulomb blockade phenomenon observed in single-electron tunneling experiments. The single-photon tunneling effect may find many applications in the emerging fields of quantum communication and information processing.
We have found experimentally that the shot noise in InAlAs-InGaAs-InAlAs Triple-Barrier Resonant-Tunneling Diodes (TBRTD) is reduced over the 2eI Poissonian value whenever their differential conductance is positive, and is enhanced over 2eI when the
differential conductance is negative. This behavior, although qualitatively similar to that found in double-barrier diodes, differs from it in important details. In TBRTDs the noise reduction is considerably larger than predicted by a semi-classical model, and the enhancement does not correlate with the strength of the negative differential conductance. These results suggest an incomplete understanding of the noise properties of multiple-barrier heterostructures.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
