Electronic magnetization of a quantum point contact measured by nuclear magnetic resonance

Abstract

We report an electronic magnetization measurement of a quantum point contact (QPC) based on nuclear magnetic resonance (NMR) spectroscopy. We find that NMR signals can be detected by measuring the QPC conductance under in-plane magnetic fields. This makes it possible to measure, from Knight shifts of the NMR spectra, the electronic magnetization of a QPC containing only a few electron spins. The magnetization changes smoothly with the QPC potential barrier height and peaks at the conductance plateau of 0.5 $\times$ $2e^2/h$. The observed features are well captured by a model calculation assuming a smooth potential barrier, supporting a no bound state origin of the 0.7 structure.

arXiv comment5 pages main text + 6 pages supplementary material. Accepted for publication in Phys. Rev. Lett

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Cited by in corpus (13)

• On the relation between the 0.7-anomaly and the Kondo effect: Geometric Crossover between a Quantum Point Contact and a Kondo Quantum Dot
• Thermoelectric Scanning Gate Interferometry on a Quantum Point Contact
• Landauer-Büttiker approach for hyperfine mediated electronic transport in the integer quantum Hall regime
• Resistively-detected NMR lineshapes in a quasi-one dimensional electron system
• Coherent Spin Amplification Using a Beam Splitter
• Detecting weak coupling in mesoscopic systems with a nonequilibrium Fano resonance
• Enhancement mechanism of the electron g-factor in quantum point contacts
• Dynamic nuclear polarization at high Landau levels in a quantum point contact
• Two-step breakdown of a local v = 1 quantum Hall state
• Dipole-like dynamical nuclear spin polarization around a quantum point contact
• Scanning Tunneling Microscopy in high vectorial magnetic fields
• The 0.7 anomaly in quantum point contact; many-body or single-electron effect?
• Dynamical nuclear spin polarization in a quantum dot with an electron spin driven by electric dipole spin resonance