Energy-level pinning and the 0.7 spin state in one dimension: GaAs quantum wires studied using finite-bias spectroscopy

Abstract

We study the effects of electron-electron interactions on the energy levels of GaAs quantum wires (QWs) using finite-bias spectroscopy. We probe the energy spectrum at zero magnetic field, and at crossings of opposite-spin-levels in high in-plane magnetic field B. Our results constitute direct evidence that spin-up (higher energy) levels pin to the chemical potential as they populate. We also show that spin-up and spin-down levels abruptly rearrange at the crossing in a manner resembling the magnetic phase transitions predicted to occur at crossings of Landau levels. This rearranging and pinning of subbands provides a phenomenological explanation for the 0.7 structure, a one-dimensional (1D) nanomagnetic state, and its high-B variants.

arXiv comment6 pages, 4 figures

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Cited by in corpus (11)

• What lurks below the last plateau: Experimental studies of the 0.7 x 2e^2/h conductance anomaly in one-dimensional systems
• On the Zero-Bias Anomaly in Quantum Wires
• Phase and amplitude response of "0.7 feature" caused by holes in silicon one-dimensional wires and rings
• Origin of the 0.25-anomaly in the nonlinear conductance of a quantum point contact
• Fractional quantization of ballistic conductance in 1D hole systems
• Direct observation of non-equilibrium spin population in quasi-one-dimensional nanostructures
• Tracking the energies of one-dimensional subband edges in quantum point contacts using dc conductance measurements
• Nuclear magnetic resonance probes for the Kondo scenario for the 0.7 feature in semiconductor quantum point contact devices
• 0.7-anomaly and magnetotransport of disordered quantum wires
• Mode-filtered electron injection into a waveguide interferometer
• Functional Renormalization Group treatment of the 0.7-analog in quantum point contacts