Two-particle dark state in the transport through a triple quantum dot

Pöltl, Christina; Emary, Clive; Brandes, Tobias

doi:10.1103/physrevb.80.115313

Cited by 76 publications

(60 citation statements)

References 47 publications

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“…A dark state forms when destructive interference of electronic wave functions decouples one of the dots from the respective lead and, as a result, the current can no longer flow through the system. This work extends the previous studies on coherent population trapping in TQDs [5][6][7] by analyzing the role of external magnetic field on the current flowing through a triple quantum dot in triangular geometry in transport regime where dark states form.…”

Section: Introductionsupporting

confidence: 54%

“…A prominent class of such systems constitute those built of three quantum dots [3,4], in which a wide variety of effects, interactions and possible configurations give rise to rich physics and consistently stimulate an extensive theoretical and experimental research. An important example of a quantum-mechanical phenomenon that can emerge in triple quantum dots (TQDs) is associated with the formation of dark states, which lead to coherent electron trapping [5][6][7][8]. A dark state forms when destructive interference of electronic wave functions decouples one of the dots from the respective lead and, as a result, the current can no longer flow through the system.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Magnetic Field on Dark States in Transport through Triple Quantum Dots

Wrześniewski

Weymann

2017

Acta Phys. Pol. A

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We theoretically study the electronic transport through a triple quantum dot system in triangular geometry weakly coupled to external metallic leads. By means of the real-time diagrammatic technique, the current and Fano factor are calculated in the lowest order of perturbation theory. The device parameters are tuned to such transport regime, in which coherent population trapping of electrons in quantum dots due to the formation of dark states occurs. The presence of such states greatly influences transport properties leading to a strong current blockade and enhanced, super-Poissonian shot noise. We consider both one-and two-electron dark states and examine the influence of magnetic field on coherent trapping in aforementioned states. When the system is in one-electron dark state, we observe a small shift of the blockade's region, whereas in the case of two-electron dark state, we show that strong magnetic field can lift the current blockade completely.

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Section: Introductionsupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Influence of Magnetic Field on Dark States in Transport through Triple Quantum Dots

Wrześniewski

Weymann

2017

Acta Phys. Pol. A

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“…[46][47][48][49][50] In this subsection we present the formula of the currents and their cross correlation in the diagonalized representation.…”

Section: Diagonalized Master Equationsmentioning

confidence: 99%

“…[45][46][47][48][49][50][60][61][62][63][64] Although the applicability of the NEGF method and the DME approach have been addressed elsewhere, 46,49,65,66 it is still unclear for unconventional fermionic systems, such as Majorana fermion system. For this MBS-dot hybrid device, it is of great interest whether the DME method could correctly reflect the information of current and noise, as questioned in a previous work.…”

Section: Applicability Of Diagonalized Master Equationsmentioning

confidence: 99%

Current noise cross correlation mediated by Majorana bound states

Lü

Shen

2014

Phys. Rev. B

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We study the transport properties of a quantum dot-Majorana hybrid system, in which each of paired Majorana bound states is connected to one quantum dot. With the help of non-equilibrium Green's function method, we obtain an exact solution of the Green's functions and calculate the currents through the quantum dots and nonlocal noise cross correlation between the currents. As a function of dot energy levels ǫ1 and ǫ2, we find that for the symmetric level configuration ǫ1 = ǫ2, the noise cross correlation is negative in the low lead voltage regime, while it becomes positive with the increase of the lead voltages. Due to the particle-hole symmetry, the cross correlation is always positive in the anti-symmetric case ǫ1 = −ǫ2. In contrast, the cross correlation of nonMajorana setups is always positive. For comparison, we also perform the diagonalized master equation calculation to check its applicability. It is found that the diagonalized master equations work well in most regimes of system parameters. Nevertheless, it shows an obvious deviation from the exact solution by the non-equilibrium Green's function method when all eigenenergies of the dot-Majorana hybrid system and simultaneously the energy intervals are comparable to the dot-lead coupling strength.PACS numbers: 03.75. Lm, 74.78.Na, 73.21.La I. INTRODUCTIONMajorana fermions, defined as fermions equivalent to own antiparticles, have been being hunted by high energy physicists for a long time.1-3 Recent years, the search of Majorana fermions has been shifted to solid-state systems, such as in the fractional quantum Hall system and p-wave superconductors.2-8 In particular, the Majorana bound states (MBSs) are predicted to appear at two ends of a semiconductor nanowire, in the proximity of an s-wave superconductor and under a proper magnetic field.9-17 The signatures for possible formation of a spatially separated pair of MBSs were reported in several experiments.18-22 Two well-separated MBSs can define a nonlocal fermion level and its occupation encodes a qubit. [5][6][7] This nonlocal topological qubit is immune to local perturbation and thus, has potential application in quantum information. However, for the same reason, it is of great challenge to coherently transfer and to read out the quantum information of the topological states. 7,17,23 It has been suggested that the MBSquantum dot hybrid system might be one of the solutions to the problem. 7,23,24 Up to now, various MBS-dot hybrid devices [23][24][25][26][27][28][29][30][31][32][33][34][35] have been proposed to detect existence of MBS,26,28,29 to modulate nonlocal correlation, 30-34 to estimate lifetime, 27 and to remove the effect of disorder. 35Therefore, it is important to investigate the transport properties of the MBS-dot hybrid systems. One of the fascinating properties of MBSs is that MBSs could induce nonlocal current cross correlation when they are coupled to mesoscopic circuits. [36][37][38][39][40][41] It has been shown that a positive cross correlation could be induced when MBSs coupl...

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“…On the theoretical side, next to fundamental studies of their eigenenergy spectrum, 17 TQDs have attracted interest mostly in a triangular arrangement, where the system symmetry gives rise to fundamental coherence phenomena. In this context, so-called "dark states" 8,18,19 and Aharonov-Bohm oscillations 8,20 have been studied. TQDs have been used as a testing ground for Kondo physics 21 and have been proposed as current rectifiers 22,23 and spin-entanglers.…”

mentioning

confidence: 99%

Spin-polarized currents in double and triple quantum dots driven by ac magnetic fields

Busl

Platero

2010

Phys. Rev. B

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We analyze transport through both a double quantum dot and a triple quantum dot with inhomogeneous Zeeman splittings in the presence of crossed dc and ac magnetic fields. We find that strongly spin-polarized current can be achieved by tuning the relative energies of the Zeeman-split levels of the dots, by means of electric gate voltages: depending on the energy level detuning, the double quantum dot works either as spin-up or spin-down filter. We show that a triple quantum dot in series under crossed dc and ac magnetic fields can act not only as spin-filter but also as spin-inverter.

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Two-particle dark state in the transport through a triple quantum dot

Cited by 76 publications

References 47 publications

Influence of Magnetic Field on Dark States in Transport through Triple Quantum Dots

Influence of Magnetic Field on Dark States in Transport through Triple Quantum Dots

Current noise cross correlation mediated by Majorana bound states

Spin-polarized currents in double and triple quantum dots driven by ac magnetic fields

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