# Persistence of the 0.7 anomaly of quantum point contacts in high magnetic fields

@article{Koop2008PersistenceOT, title={Persistence of the 0.7 anomaly of quantum point contacts in high magnetic fields}, author={E. J. Koop and Alexandru Ionut Lerescu and J. D. Liu and Bart Jan van Wees and Dirk Reuter and Andreas Dirk Wieck and Caspar H. van der Wal}, journal={arXiv: Mesoscale and Nanoscale Physics}, year={2008} }

The spin degeneracy of the lowest subband that carries one-dimensional electron transport in quantum point contacts appears to be spontaneously lifted in zero magnetic field due to a phenomenon that is known as the 0.7 anomaly. We measured this energy splitting, and studied how it evolves into a splitting that is the sum of the Zeeman effect and a field-independent exchange contribution when applying a magnetic field. While this exchange contribution shows sample-to-sample fluctuations, it is…

## One Citation

Electron-Electron Interactions in Quantum Point Contacts and Finite Quantum Wires

- Physics
- 2007

This thesis is on the effect of electron-electron interactions on the transport properties in two cases: (A) Finite length clean quantum wires and (B) point-like constrictions. In both situations,…

## References

SHOWING 1-10 OF 21 REFERENCES

Scenario for the 0.7-conductance anomaly in quantum point contacts

- Physics
- 2003

Effects of spontaneous spin polarization in quantum point contacts (QPC's) are investigated for a realistic semiconductor device structure using the Kohn-Sham local spin-density formalism. At maximal…

Kondo model for the "0.7 anomaly" in transport through a quantum point contact.

- PhysicsPhysical review letters
- 2002

An Anderson model for transport through a point contact analyzed in the Kondo limit explains the observed gate-voltage, temperature, magnetic field, and bias- voltages and a spin-polarized current is predicted even for low magnetic fields.

Anomalous spin-dependent behavior of one-dimensional subbands

- Physics
- 2005

We report an electron interaction effect in GaAs/AlGaAs quantum wires. Using dc-bias spectroscopy, we show that large and abrupt changes occur to the energies of spin-down (lower energy) states as…

Low-temperature fate of the 0.7 structure in a point contact: a Kondo-like correlated state in an open system.

- PhysicsPhysical review letters
- 2002

Evidence is presented that the disappearance of the 0.7 structure at very low temperature signals the formation of a Kondo-like correlated spin state, including a zero-bias conductance peak that splits in a parallel field, scaling of conductance to a modified Kondo form, and consistency between peak width and the Kondo temperature.

Shot-noise signatures of 0.7 structure and spin in a quantum point contact.

- PhysicsPhysical review letters
- 2006

Comparison to a phenomenological model with density-dependent level splitting yields good quantitative agreement on simultaneous measurement of shot noise and dc transport in a quantum point contact as a function of source-drain bias, gate voltage, and in-plane magnetic field.

Interaction effects at crossings of spin-polarized one-dimensional subbands.

- PhysicsPhysical review letters
- 2003

It is suggested that at low densities a spontaneous spin splitting occurs whenever two 1D subbands of opposite spins cross and develops into a plateau and lowers to 2e(2)/h.

Magnetic impurity formation in quantum point contacts

- PhysicsNature
- 2006

Detailed numerical density-functional calculations are presented that reveal the formation of an electronic state with a spin-1/2 magnetic moment in the channel under very general conditions, and show that such an impurity will also form at large magnetic fields, for a specific value of the field, and sometimes at the opening of the second transverse mode in the QPC.

From quantum point contacts to quantum wires : Density-functional calculations with exchange and correlation effects

- Physics
- 2006

We numerically analyze the conductance and spin polarization of realistic quantum point contacts (QPCs) using density-functional theory, including both exchange and correlation effects. The…

Bias and temperature dependence of the 0.7 conductance anomaly in quantum point contacts

- Physics
- 2000

The 0.7 (2e^2/h) conductance anomaly is studied in strongly confined, etched GaAs/GaAlAs quantum point contacts, by measuring the differential conductance as a function of source-drain and gate bias…