2013/07/31 by Boris Brun, B. Brun, F. Martins +16 · 61 citations
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Anomaly (physics) #Condensed matter physics #Conductance #Crystal (programming language) #Electron #Kondo effect #Microscope #Molecular Junctions and Nanostructures #Optics #Physics #Quantum #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #Spin (aerodynamics) #Wigner crystal #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1038/ncomms5290
published in Nature Communications 5(1), 4290 (Nature Portfolio)
openalex publication_date 2014/06/30 · arxiv created 2014/12/18 · arxiv updated 2014/12/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Quantum point contacts exhibit mysterious conductance anomalies in addition to well known conductance plateaus at multiples of 2e2/h. These 0.7 and zero-bias anomalies have been intensively studied, but their microscopic origin in terms of many-body effects is still highly debated. Here we use the charged tip of a scanning gate microscope to tune in situ the electrostatic potential of the point contact. While sweeping the tip distance, we observe repetitive splittings of the zero-bias anomaly, correlated with simultaneous appearances of the 0.7 anomaly. We interpret this behaviour in terms of alternating equilibrium and non-equilibrium Kondo screenings of different spin states localized in the channel. These alternating Kondo effects point towards the presence of a Wigner crystal containing several charges with different parities. Indeed, simulations show that the electron density in the channel is low enough to reach one-dimensional Wigner crystallization over a size controlled by the tip position.