A Novel Test Bed for Non-Equilibrium Many-Body Physics
April 3, 2018 | ETH ZurichEstimated reading time: 2 minutes
Whether a material is, for example, a metal or an insulator depends on a range of microscopic details, including the strength of interactions between electrons, the presence of impurities and the number of dimensions through which the charge carriers can propagate. This complexity makes the prediction of electronic properties in solid-state systems highly challenging.
Image caption: Atoms are shaped into a wire using laser light. Their flow can be influenced by projecting a variable number of light obstacles focussed on the wire with a microscope objective. (Image: Esslinger group/ETH Zurich)
Understanding the behaviour of electrons in a material becomes all the more difficult when they move through a periodic potential, for example in a crystal. Then phenomena such as superfluidity, which is associated with a large conductance, can compete with interference effects that turn the material into an insulator.
Martin Lebrat, together with colleagues in the group of Tilman Esslinger at the Institute for Quantum Electronics of ETH Zurich and collaborators at the University of Geneva and the École Polytechnique Fédérale de Lausanne (EPFL) have now tackled the problem by performing experiments in a perfectly clean artificial material that they can control with great accuracy and flexibility.
Atoms are shaped into a wire using laser light
Atoms are shaped into a wire using laser light. Their flow can be influenced by projecting a variable number of light obstacles focussed on the wire with a microscope objective. (Image: Esslinger group/ETH Zurich)
As they report in a paper published in Physical Review X ("Band and correlated insulators of cold fermions in a mesoscopic lattice"), they used laser light to create short one-dimensional lattice structures connected to two reservoirs of ultracold lithium-6 atoms.
In this setup they can measure the conductance of the wire while having exquisite control over all relevant parameters, including the length and height of the lattice and the interactions between the particles being transported through it.
In their experiments, they observed the emergence of a band-insulating phase with weak interactions. When they tuned the interactions from weakly to strongly attractive, they discovered that this insulating state persists, hinting at the presence of a so-called Luther-Emery liquid, an original phase that has been predicted in 1974 and which is distinctive of the one-dimensional character of the structure.
The experimental work is supported by simulations, and taken together these results demonstrate the simultaneous control of interactions and quantum interferences in cold-atom devices. This should be not only interesting with a view to exploring the behaviour of electrons moving through materials; the flexibility provided by the approach of Lebrat and co-workers also means that they can engineer complex structures with novel functionalities that are not available in electronic systems.
Suggested Items
Connect the Dots: Best Practices for Prototyping
09/21/2023 | Matt Stevenson -- Column: Connect the DotsPCB prototyping is a critical juncture during an electronic device’s journey from concept to reality. Regardless of a project’s complexity, the process of transforming a design into a working board is often enlightening in terms of how a design can be improved before a PCB is ready for full production.
The Drive Toward UHDI and Substrates
09/20/2023 | I-Connect007 Editorial TeamPanasonic’s Darren Hitchcock spoke with the I-Connect007 Editorial Team on the complexities of moving toward ultra HDI manufacturing. As we learn in this conversation, the number of shifting constraints relative to traditional PCB fabrication is quite large and can sometimes conflict with each other.
Asia/Pacific AI Spending Surge to Reach a Projected $78 Billion by 2027
09/19/2023 | IDCAsia/Pacific spending on Artificial Intelligence (AI) ), including software, services, and hardware for AI-centric systems will grow to $78.4 billion in 2027, according to International Data Corporation's latest Worldwide Artificial Intelligence Spending Guide.
Intel to Sell Minority Stake in IMS Nanofabrication Business to TSMC
09/13/2023 | IntelIntel Corporation announced that it has agreed to sell an approximately 10% stake in the IMS Nanofabrication business to TSMC. TSMC’s investment values IMS at approximately $4.3 billion, consistent with the valuation of the recent stake sale to Bain Capital Special Situations.
RAF Invests in BAE Systems’ Most Advanced Fighter Pilot Helmet
09/13/2023 | BAE SystemsThe UK Ministry of Defence (MOD) has awarded BAE Systems a contract to develop its Striker II Helmet Mounted Display (HMD) for the Royal Air Force (RAF) Typhoon fleet. The contract, valued at £40m, will create and sustain more than 200 highly-skilled jobs at BAE Systems’ sites in Kent and Lancashire working directly on the Striker II programme. In total, the Typhoon programme sustains more than 20,800 jobs across the UK.