Evidence for localization and 0.7 anomaly in hole quantum point contacts

Abstract

Quantum point contacts implemented in p-type GaAs/AlGaAs heterostructures are investigated by low-temperature electrical conductance spectroscopy measurements. Besides one-dimensional conductance quantization in units of $2e^2/h$ a pronounced extra plateau is found at about $0.7(2e^2/h)$ which possesses the characteristic properties of the so-called "0.7 anomaly" known from experiments with n-type samples. The evolution of the 0.7 plateau in high perpendicular magnetic field reveals the existence of a quasi-localized state and supports the explanation of the 0.7 anomaly based on self-consistent charge localization. These observations are robust when lateral electrical fields are applied which shift the relative position of the electron wavefunction in the quantum point contact, testifying to the intrinsic nature of the underlying physics.

4.2 pages, 3 figures

References in corpus (7)

• Magnetic impurity formation in quantum point contacts
• Aharonov-Bohm oscillations in the presence of strong spin-orbit interactions
• Ballistic transport in induced one-dimensional hole systems
• 0.7 Structure and Zero Bias Anomaly in Ballistic Hole Quantum Wires
• The theory of the "0.7 anomaly" in quantum point contacts
• Observation of excited states in a p-type GaAs quantum dot
• High-quality quantum point contact in two-dimensional GaAs (311)A hole system

Cited by in corpus (17)

• What lurks below the last plateau: Experimental studies of the 0.7 x 2e^2/h conductance anomaly in one-dimensional systems
• Odd and even Kondo effects from emergent localisation in quantum point contacts
• Transport Properties of Clean Quantum Point Contacts
• Anomalous spin-resolved point-contact transmission of holes due to cubic Rashba spin-orbit coupling
• Spin-orbit splitting and effective masses in p-type GaAs two-dimensional hole gases
• Observation of the Kondo Effect in a Spin-3/2 Hole Quantum Dot
• Few-hole double quantum dot in an undoped GaAs/AlGaAs heterostructure
• On the relation between the 0.7-anomaly and the Kondo effect: Geometric Crossover between a Quantum Point Contact and a Kondo Quantum Dot
• Counting statistics of hole transfer in a p-type GaAs quantum dot with dense excitation spectrum
• Spin fluctuations in the 0.7-anomaly in quantum point contacts
• Extreme sensitivity of the spin-splitting and 0.7 anomaly to confining potential in one-dimensional nanoelectronic devices
• Interplay of fractional quantum Hall states and localization in quantum point contacts
• Origins of conductance anomalies in a p-type GaAs quantum point contact
• Ballistic quantum transport through Ge/Si core/shell nanowires
• Anisotropic Zeeman splitting in p-type GaAs quantum point contacts
• Temperature Dependence of Conductance and Thermopower Anomalies of Quantum Point Contacts
• Aharonov-Bohm rings with strong spin-orbit interaction: the role of sample-specific properties