Enhanced shot noise in asymmetric interacting two-level systems

Carmi, Assaf; Oreg, Yuval

doi:10.1103/physrevb.85.045325

Cited by 20 publications

(21 citation statements)

References 38 publications

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“…As derived in Ref. [13], the Fano factor of the super-Poissonian noise in a telegraphic system is described by the expression…”

Section: Numerical Simulationsmentioning

confidence: 98%

“…Theory has shown that in single-level QDs the Pauli exclusion principle and the repulsive Coulomb interaction result in anti-bunching [7][8][9][10]. However, occupation dynamics in multi-level QDs can give rise to bunching, and correspondingly, super-Poissonian noise [11][12][13]. The electron transport in an interacting two-level system is a telegraphic process if the tunnel couplings of one level are much stronger than of the other [13].…”

Section: Introductionmentioning

confidence: 99%

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Blocking-state influence on shot noise and conductance in quantum dots

et al. 2018

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Quantum dots (QDs) investigated through electron transport measurements often exhibit varying, state-dependent tunnel couplings to the leads. Under specific conditions, weakly coupled states can result in a strong suppression of the electrical current and they are correspondingly called blocking states. Using the combination of conductance and shot noise measurements, we investigate blocking states in carbon nanotube (CNT) QDs. We report negative differential conductance and super-Poissonian noise. The enhanced noise is the signature of electron bunching, which originates from random switches between the strongly and weakly conducting states of the QD. Negative differential conductance appears here when the blocking state is an excited state. In this case, at the threshold voltage where the blocking state becomes populated, the current is reduced. Using a master equation approach, we provide numerical simulations reproducing both the conductance and the shot noise pattern observed in our measurements. arXiv:1801.00286v1 [cond-mat.mes-hall]

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“…As derived in Ref. [13], the Fano factor of the super-Poissonian noise in a telegraphic system is described by the expression…”

Section: Numerical Simulationsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Blocking-state influence on shot noise and conductance in quantum dots

et al. 2018

View full text Add to dashboard Cite

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“…On the other hand, the presence of localized states in a conductor will give rise to super-Poissionian noise, depending on the ratio of traversal and localized time scales of the current carrying electrons [33]. The latter applies to conductors having twolevel fluctuators [34]. Hence, for the purpose of simplifying the analysis we will restrict noise spectroscopy to junctions having neither VITLS signatures nor Kondo-like zero-bias anomalies in the differential conductance, but that only show molecular signatures as step-down or step-up features.…”

Section: B Experimental Observationsmentioning

confidence: 99%

Molecule-assisted ferromagnetic atomic chain formation

Kumar

Ruitenbeek

2015

Phys. Rev. B

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One dimensional systems strongly enhance the quantum character of electron transport. Such systems can be realized in 5d transition metals Au, Pt, and Ir, in the form of suspended monatomic chains between bulk leads. Atomic chains between ferromagnetic leads would open up many perspectives in the context of spin-dependent transport and spintronics, but the evidence suggests that for pure metals only the mentioned three 5d metals are susceptible to chain formation. It has been argued that the stability of atomic chains made up from ferromagnetic metals is compromised by the same exchange interaction that produces the local moments. Here we demonstrate that magnetic atomic chains can be induced to form in break junctions under the influence of light molecules. Explicitly, we find deuterium assisted chain formation in the 3d ferromagnetic transition metals Fe and Ni. Chain lengths up to eight atoms are formed upon stretching the ferromagnetic atomic contact in deuterium atmosphere at cryogenic temperatures. From differential conductance spectra vibronic states of D 2 can be identified, confirming the presence of deuterium in the atomic chains. Shot noise spectroscopy indicates the presence of weakly spin polarized transmission channels.

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“…Alternatively, one could repeatedly measure the time τ it takes for the number of measured quantum jumps to reach n and construct a probability density distribution P (τ (n)), as we demonstrate in Fig.(1). The first quantity, n(t), is an example of a fixed-time statistic [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], while τ (n) is an example of a fluctuating-time statistic [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Considering the important role time-dependent fluctuations have, analysis of quantum fluctuations has therefore been focused on calculating either fixed-time and fluctuating-time statistics, and exploring the relationship between the two [42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Counting quantum jumps: A summary and comparison of fixed-time and fluctuating-time statistics in electron transport

Rudge

Kosov

2019

The Journal of Chemical Physics

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In quantum transport through nanoscale devices, fluctuations arise from various sources: the discreteness of charge carriers, the statistical non-equilibrium that is required for device operation, and unavoidable quantum uncertainty. As experimental techniques have improved over the last decade, measurements of these fluctuations have become available. They have been accompanied by a plethora of theoretical literature using many different fluctuation statistics to describe the quantum transport. In this paper, we overview three prominent fluctuation statistics: full counting, waiting time, and first-passage time statistics. We discuss their weaknesses and strengths, and explain connections between them in terms of renewal theory. In particular, we discuss how different information can be encoded in different statistics when the transport is non-renewal, and how this behavior manifests in the measured physical quantities of open quantum systems. All theoretical results are illustrated via a demonstrative transport scenario: a Markovian master equation for a molecular electronic junction with electron-phonon interactions. We demonstrate that to obtain non-renewal behavior, and thus to have temporal correlations between successive electron tunneling events, there must be a strong coupling between tunneling electrons and out-of-equilibrium quantized molecular vibrations.

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Enhanced shot noise in asymmetric interacting two-level systems

Cited by 20 publications

References 38 publications

Blocking-state influence on shot noise and conductance in quantum dots

Blocking-state influence on shot noise and conductance in quantum dots

Molecule-assisted ferromagnetic atomic chain formation

Counting quantum jumps: A summary and comparison of fixed-time and fluctuating-time statistics in electron transport

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