Infrared vaLLey control of moiré qUantum MatErials

Descripción del proyecto

Luz polarizada circularmente: polarización de valle en materiales muaré

Los portadores, como electrones, huecos o excitones, se describen convencionalmente por su carga y espín, los grados de libertad del sistema físico que definen el estado del sistema. Más recientemente, el valle —un extremo energético en la estructura de banda electrónica— se ha considerado un nuevo grado de libertad. El equipo del proyecto ILLUME, que cuenta con el apoyo de las Acciones Marie Skłodowska-Curie, estudiará el uso de luz polarizada circularmente para lograr la polarización valle en materiales cuánticos muaré. Esto podría conducir a la llamada superconductividad de banda plana y a los aislantes correlacionados. Los investigadores analizarán la dispersión entre valles en canales unidimensionales que conducen a interferencias superconductoras e investigarán las fases superconductoras y los aislantes correlacionados en sistemas muaré de banda plana.

Objetivo

A key ingredient governing the behaviour of electron dynamics in condensed matter systems is the valley degree of freedom. This fellowship aims at inducing topological (or valley-polarised) electronic phases in moiré systems and explore their tunability. Moiré quantum materials present a high degree of tunability as the ratio between interaction strength and electronic bandwidth can be optimised, resulting in flat bands and correlated electronic states. Control of such phases with circularly polarised light would allow to understand the valley-polarisation, topological protection, and the mechanisms underlying the emergence of flat-band superconductivity and correlated insulators. The project will use an interdisciplinary methodology combining electronic transport techniques with infrared far-field irradiation and near field imaging, to create, manipulate and explore novel phases with non-trivial topology (valley polarisation) in moiré materials. The researcher will conduct transport measurement with circularly polarised light to selectively induce inter-valley scattering in 1D channels and explore superconducting interferences in this regime. The project will also quantify the influence of circularly polarised light (CPL) on the superconducting phases and correlated insulators in flat band moiré systems, in order to comprehend the interplay of strongly correlated electronic states with CPL and understand their origin. The fellowship will control and explore novel phases with non-trivial topology in moiré materials, providing new understanding of valley-polarised phases. This objective is a steppingstone towards the creation of new optoelectronic devices such as photonic diodes, optical transistors and logic circuits, and could lead to new concepts as topological nanophotonics for optical information processing.