Low-frequency noise of quantum point contacts in the ballistic and quantum Hall regime

Liefrink, F.; Scholten, A.J.; Dekker, Cees; Eppenga, R.; Houten, H. van; Foxon, C.T.

doi:10.1016/0921-4526(91)90714-p

Cited by 24 publications

(13 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, we do not yet have an in-depth understanding of its resistance fluctuations, which have been found to be important in mesoscopic structures fabricated from such heterostructures. [3][4][5][6][7][8][9] Various mechanisms, such as trapping of electrons, 4-6 changes in the remote impurity configuration, 7 and DX centers, 8 have been proposed as the source of such fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B

View full text Add to dashboard Cite

We study low-frequency noise in selectively doped GaAs/Al x Ga 1Ϫx As quantum point contact and Hall bar structures. Experiments are carried out at 4.2 K and constant magnetic fields where noise in both diagonal and Hall voltages is measured using a four-terminal lock-in technique. In all cases, for low currents and low frequencies, we find the size of excess voltage noise power to be quadratic in current and, furthermore, Hall voltage noise power to be quadratic in magnetic field. Resistance fluctuations of the quantum point contact samples are mostly dominated by a single two-level or multilevel switching event that leads to a Lorentzian noise spectrum, whereas resistance fluctuations of the Hall bar structures exhibit 1/f noise, which results from the superposition of many independent switching events. Three possible sources of 1/f noise, i.e., fluctuations in carrier density, mobility, and quantum interference corrections, are considered in the analysis of the Hall bar data. From the size of 1/f noise in the Hall voltage, we deduce an upper bound for the size of carrier density fluctuations that is so small that we rule out electron trapping as a main source of resistance fluctuations in the quantum point contact structures. Instead, we explain observed low-frequency noise in both mesoscopic and macroscopic structures by fluctuations in the remote impurity configuration.

show abstract

Section: Introductionmentioning

confidence: 99%

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…Note that the frequency dependent S͑n͒ was shown (neglecting Coulomb interactions between electrons) to decrease linearly with n with S͑n cutoff ͒ 0 for hn cutoff eV DS (i.e., for V DS 1 mV, n cutoff 250 GHz) [10]. The first attempt to measure noise in a QPC was by Li et al [11] followed later by others [12,13]. All measurements had been restricted to low frequencies ͑n , 100 kHz͒ where 1͞f noise or fluctuations and instabilities of the conductance are dominant, and the noise power was found to have a square dependence on the dc current and not the expected linear dependence.…”

mentioning

confidence: 99%

Temporal Correlation of Electrons: Suppression of Shot Noise in a Ballistic Quantum Point Contact

et al. 1995

View full text Add to dashboard Cite

Wideband shot noise, associated with dc current flow through a quantum point contact (QPC), is measured in the microwave frequency range of 8-18 GHz. As the number of conducting channels in the QPC changes the noise power oscillates. Consistent with existing theories, the noise peaks depend linearly on the dc current. Surprisingly, however, in the pinch off region, where QPC is expected to behave as a classical injector, we find strong noise suppression, possibly mediated by the Coulomb interaction.

show abstract

“…This source of current fluctuations is called shot noise. [25][26][27][28][29][30][31][32] For brevity, I will use the same name, the shot noise, also for current fluctuations and for the current-current correlation function P 34 .…”

Section: A Setupmentioning

confidence: 99%

Single-particle shot noise at nonzero temperature

Moskalets

2017

Phys. Rev. B

View full text Add to dashboard Cite

The state of a single particle injected onto the surface of the Fermi sea is a pure state if the temperature is zero and is a mixed state if the temperature is finite. Moreover, the state of an injected particle is orthogonal to the state of the Fermi sea at zero temperature, while it is not orthogonal at non-zero temperature. These changes in the quantum state of the injected particles can be detected using the temperature dependence of the shot noise that is generated when the particles one by one pass through a semitransparent quantum point contact. Namely, the shot noise produced by the mixed state is suppressed in comparison with the noise of the pure state. In addition, the correlations between the injected particles and the underlying Fermi sea, present at non-zero temperature, do enhance the shot noise. Furthermore, antibunching of injected particles with possible thermal excitations coming from another input channel of a quantum point contact does suppress shot noise. Here I analyze in detail these three effects, which are responsible for the temperature dependence of the shot noise, and discuss how to distinguish them experimentally.

show abstract

Low-frequency noise of quantum point contacts in the ballistic and quantum Hall regime

Cited by 24 publications

References 10 publications

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B

Temporal Correlation of Electrons: Suppression of Shot Noise in a Ballistic Quantum Point Contact

Single-particle shot noise at nonzero temperature

Contact Info

Product

Resources

About

Low-frequency noise of quantum point contacts in the ballistic and quantum Hall regime

Cited by 24 publications

References 10 publications

Resistance fluctuations inGaAs/AlxKurdak1, Chen2, Tsui3 et al. 1997Phys. Rev. B

Resistance fluctuations inGaAs/AlxKurdak1, Chen2, Tsui3 et al. 1997Phys. Rev. B

Temporal Correlation of Electrons: Suppression of Shot Noise in a Ballistic Quantum Point Contact

Single-particle shot noise at nonzero temperature

Contact Info

Product

Resources

About

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B

Resistance fluctuations inGaAs/Alx
Kurdak
¹
,
Chen
²
,
Tsui
³

et al. 1997
Phys. Rev. B