Tunable 0.7 conductance plateau in quantum dots

Chung, Yunchul; Jo, Sanghyun; Chang, Dong-In; Lee, Hu-Jong; Zaffalon, M.; Umansky, V.; Heiblum, Moty

doi:10.1103/physrevb.76.035316

Cited by 13 publications

(9 citation statements)

References 17 publications

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“…It was in this context that it was shown to have T = 0 phase transition [17][18][19][20][21][22] . Studies based on the two impurity Anderson model in the absence of a magnetic field have revealed a discontinuous change in spectral density at the Fermi level at the transition 23,24 . Other studies have shown that the transition is very robust, occurring away from particle-hole symmetry 25 and even away from the Kondo regime with U 1 = U 2 = U 12 = 0 15,1626,27 .…”

Section: Modelmentioning

confidence: 99%

Magnetic field induced quantum criticality and the Luttinger sum rule

et al. 2018

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We show that when there is a sudden transition from a small to a large Fermi surface at a field induced quantum critical point -similar to what may have been observed in some heavy fermion compounds -an additional term has to be taken into account in the Luttinger-Friedel sum rule. We calculate this additional term for a local model which has a field induced quantum critical point (QCP) and show that it changes abruptly at the transition, such that it satisfies a generalized Luttinger-Friedel sum rule on each side of the transition, and characterizes the two Fermi liquid phases separated by the QCP as a discrete (topological) index.

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Section: Modelmentioning

confidence: 99%

Magnetic field induced quantum criticality and the Luttinger sum rule

et al. 2018

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“…In spite of the long research history, it still remains a considerable interest in terms of many-body effect such as the 0.7 anomaly [3][4][5][6][7][8][9][10][11][12][13] . Thus, to precisely clarify the mesoscopic transport in QPC from various points of view is still of scientific significance.…”

Section: Introductionmentioning

confidence: 99%

“…Owing to its characteristic property that the conductance is quantized in units of 2e 2 /h ∼ (12.9 kΩ) −1 due to the ballistic conduction and the wave nature of electrons, QPC has attracted great attention as an ideal realization of Landauer picture of mesoscopic transport. In spite of the long research history, it still remains a considerable interest in terms of many-body effect such as the 0.7 anomaly [3][4][5][6][7][8][9][10][11][12][13] . Thus, to precisely clarify the mesoscopic transport in QPC from various points of view is still of scientific significance.…”

Section: Introductionmentioning

confidence: 99%

Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

et al. 2016

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We report a precise experimental study on the shot noise of a quantum point contact (QPC) fabricated in a GaAs/AlGaAs based high-mobility two-dimensional electron gas (2DEG). xThe combination of unprecedented cleanliness and very high measurement accuracy has enabled us to discuss the Fano factor to characterize the shot noise with a precision of 1 %. We observed that the shot noise at zero magnetic field exhibits a slight enhancement exceeding the single particle theoretical prediction, and that it gradually decreases as a perpendicular magnetic field is applied. We also confirmed that this additional noise completely vanishes in the quantum Hall regime. These phenomena can be explained by the electron heating effect near the QPC, which is suppressed with increasing magnetic field.

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“…In 1996, Thomas and co-workers observed an additional plateau at 0.7 G 0 in the AlGaAs/GaAs quantum point contact (QPC) in the absence of any magnetic field [4]. Since then, this anomalous plateau, usually referred to as the "0.7 structure", has been observed in both QPCs and relatively long 1D quantum wires [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Possible origin of the 0.5 plateau in the ballistic conductance of quantum point contacts

et al. 2009

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A non-equilibrium Green function formalism (NEGF) is used to study the conductance of a side-gated quantum point contact (QPC) in the presence of lateral spin-orbit coupling (LSOC). A small difference of bias voltage between the two side gates (SGs) leads to an inversion asymmetry in the LSOC between the opposite edges of the channel. In single electron modeling of transport, this triggers a spontaneous but insignificant spin polarization in the QPC. However, the spin polarization of the QPC is enhanced substantially when the effect of electron-electron interaction is included. The spin polarization is strong enough to result in the occurrence of a conductance plateau at 0.5G 0 (G 0 = 2e 2 /h) in the absence of any external magnetic field. In our simulations of a model QPC device, the 0.5 plateau is found to be quite robust and survives up to a temperature of 40K. The spontaneous spin polarization and the resulting magnetization of the QPC can be reversed by flipping the polarity of the source to drain bias or the potential difference between the two SGs. These numerical simulations are in good agreement with recent experimental results for side-gated QPCs made from the low band gap semiconductor InAs.

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Tunable 0.7 conductance plateau in quantum dots

Cited by 13 publications

References 17 publications

Magnetic field induced quantum criticality and the Luttinger sum rule

Magnetic field induced quantum criticality and the Luttinger sum rule

Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

Possible origin of the 0.5 plateau in the ballistic conductance of quantum point contacts

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