Enhanced Shot Noise in Tunneling through a Stack of Coupled Quantum Dots

Barthold, P.; Hohls, Frank; Maire, Niels; Pierz, K.; Haug, Rolf J.

doi:10.1103/physrevlett.96.246804

Cited by 49 publications

(85 citation statements)

References 21 publications

(26 reference statements)

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“…Applying the Master equation model from [32], we find super-Poissonian noise with a characteristic two-peak structure around the location of the current resonance, see Fig. 5(c,d), which is very similar to recent experimental results [42]. Such a behavior relies on the interplay of two resonances at the same bias, see Fig.…”

Section: Current Fluctuations and Shot Noisesupporting

confidence: 71%

Theory of Nonlinear Transport for Ensembles of Quantum Dots

Kießlich¹,

Wacker²,

Schöll³

2008

Semiconductor Nanostructures

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Section: Current Fluctuations and Shot Noisesupporting

confidence: 71%

Theory of Nonlinear Transport for Ensembles of Quantum Dots

Kießlich¹,

Wacker²,

Schöll³

2008

Semiconductor Nanostructures

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“…In our case, as the exciton decays into surface plasmon, the non-Markovian effect from the plasmon reservoir may re-excite it now and then, such that the Fano factor is enhanced. One notes that this kind of enhancement due to quantum coherence has recently been observed in the tunneling through a stack of coupled quantum dots [22] and explained theoretically [23].…”

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confidence: 99%

Proposal for detection of non-Markovian decay via current noise

Chen

2008

Phys. Rev. B

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We propose to detect non-Markovian decay of an exciton qubit coupled to multi-mode bosonic reservoir via shot-noise measurements. Non-equilibrium current noise is calculated for a quantum dot embedded inside a p-i-n junction. An additional term from non-Markovian effect is obtained in the derivation of noise spectrum. As examples, two practical photonic reservoirs, photon vacuum with the inclusion of cut-off frequency and surface plasmons, are given to show that the noise may become super-Poissonian due to this non-Markovian effect. Utilizing the property of super-radiance is further suggested to enhance the noise value.PACS numbers: 03.65. Yz, 72.70.+m, 73.20.Mf, Introduction.-Due to rapid progress of quantum information science, great attention has been focused on the dynamics of systems interacting with their surroundings. Radiative decay of a two-level atom maybe one of the most obvious examples in this issue and can be traced back to such early works as that of Albert Einstein in 1917.[1] While Markovian approximation is widely adopted to treat decoherence and relaxation problems, non-Markovian dynamics of qubit systems have attracted increasing attention lately. [2] Turning to solid state systems, an exciton in a quantum dot (QD) can be viewed as a two-level system. Radiative properties of QD excitons, such as super-radiance [3] and Purcell effect [4], have attracted great attention during the past two decades. Utilizing QD excitons for quantum gate operations have also been demonstrated experimentally.[5] With the advances of fabrication technologies, it is now possible to embed QDs inside a p-i-n structure [6], such that the electron and hole can be injected separately from opposite sides. This allows one to examine the exciton dynamics in a QD via electrical currents [7].Recently, the interest in measurements of shot noise in quantum transport has risen owing to the possibility of extracting valuable information not available in conventional dc transport experiments [8]. In this work, we propose to detect non-Markovian decay of a exciton qubit via the current noise of a QD p-i-n junction. Without making Markovian approximation to the exciton-boson interaction, we analytically show that the Fano factor (zero-frequency noise) may become super-Poissonian. As examples, two practical photonic environments, photon vacuum with the inclusion of cut-off frequency and surface plasmons, are given to show this non-Markovian effect. To enhance the noise value, we further suggest utilizing the property of super-radiance.The model.-QDs can now be embedded in a p-i-n junction, such that many applications can be accomplished by electrical control. As shown in Fig. 1, we wish to see

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“…In particular, the bunching of tunneling events, observable as an increased shot noise power, can characterize the Coulomb interaction in the transport through multilevel quantum dots. [1][2][3][4][5][6][7][8] The sequence of tunneling events is correlated by the Coulomb blockade and depends on the effective tunneling rates and internal level structure, which allows for the detection of spin-dependent tunneling through quantum dots. 9 Injection of electrons from spin-polarized leads may result in a spin-dependent blockade as shown by Ciorga et al [10][11][12] The spin blockade effect 13 has been observed in the addition spectrum of a quantum dot in a magnetic field 14,15 as a modulation of the Coulomb blockade peak amplitude or in the occurrence of negative differential resistance.…”

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confidence: 99%

Spin-dependent shot noise enhancement in a quantum dot

et al. 2013

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The spin-dependent dynamical blockade was investigated in a lateral quantum dot in a magnetic field. Spinpolarized edge channels in the two-dimensional leads and the spatial distribution of Landau orbitals in the dot modulate the tunnel coupling of the quantum dot level spectrum. In a measurement of the electron shot noise we observe a pattern of super-Poissonian noise which is correlated to the spin-dependent competition between different transport channels. DOI: 10.1103/PhysRevB.88.041304 PACS number(s): 72.70.+m, 72.25.−b, 73.23.Hk, 73.63.Kv The prospect of using the electron spin as a basic element of information for quantum computation and new semiconductor devices has stimulated the study of spindependent phenomena. Many of these applications require control of the spin-dependent dynamics in the transfer of charge through single electron devices. Fluctuations of the current contain information about these dynamics and the underlying mechanisms can be probed in a measurement of the electron shot noise. In particular, the bunching of tunneling events, observable as an increased shot noise power, can characterize the Coulomb interaction in the transport through multilevel quantum dots.1-8 The sequence of tunneling events is correlated by the Coulomb blockade and depends on the effective tunneling rates and internal level structure, which allows for the detection of spin-dependent tunneling through quantum dots.9 Injection of electrons from spin-polarized leads may result in a spin-dependent blockade as shown by Ciorga et al. [10][11][12] The spin blockade effect 13 has been observed in the addition spectrum of a quantum dot in a magnetic field 14,15 as a modulation of the Coulomb blockade peak amplitude or in the occurrence of negative differential resistance. 16 While these measurements studied the average conductance, additional dynamical information can be obtained by shot noise detection techniques.In this Rapid Communication we present our measurements of the electron shot noise in the spin blockade regime. At finite bias we observe super-Poissonian noise at the Coulomb blockade peak. The shot noise enhancement follows a regular pattern correlated to the crossing Landau levels in a magnetic field. Interpretation in terms of the dynamical channel blockade mechanism suggests an underlying competition between transport channels with different spin.The quantum dot is defined by local anodic oxidation of a GaAs/AlGaAs heterostructure with a two-dimensional electron system 34 nm below the surface. 16 The electron density of the heterostructure is 4.6 × 10 11 cm −2 and the mobility is 6.4 × 10 5 cm 2 /V s. Measurements were performed in a 3 He/ 4 He dilution refrigerator at a temperature of 100 mK. Current fluctuations are converted to voltage fluctuations by RLC circuits in a cross-correlation configuration [ Fig. 1(a)] centered at 1 MHz. The voltage fluctuations are amplified by cryogenic high-electron-mobility transistor (Refs. 17 and 18) and digitized at room temperature. The real part of the cross-corr...

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Enhanced Shot Noise in Tunneling through a Stack of Coupled Quantum Dots

Cited by 49 publications

References 21 publications

Theory of Nonlinear Transport for Ensembles of Quantum Dots

Theory of Nonlinear Transport for Ensembles of Quantum Dots

Proposal for detection of non-Markovian decay via current noise

Spin-dependent shot noise enhancement in a quantum dot

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