Programma: PRIN
Responsabile scientifico per il dipartimento: Cesare Franchini
Struttura principale: DIFA
Data inizio e data fine: dal 28/09/2023 al 28/09/2025
Ossidi di metalli di transizione: nuovi materiali per l’elettronica
Il progetto studia gli ossidi di iridio con forti interazioni spin-orbita per comprenderne le proprietà magnetiche e di trasporto, con applicazioni nella spintronica e nella fisica della materia condensata.
Transition Metal Oxides: New Materials for Electronics
The project investigates iridium oxides with strong spin-orbit coupling to understand their magnetic and transport properties, with applications in spintronics and condensed matter physics.
Abstract
Transition-metal oxides display a variety of physical properties, thus making them a vast playground for fundamental investigationsand appealing for technological applications. Ultimately, this richness derives from the spin, charge, orbital and lattice degrees offreedom simultaneously at play, giving rise to a delicate competition between various energy scales of comparable magnitude. Thismakes transition metal oxides sensitive to external stimuli, such as electric and magnetic fields, physical and chemical pressure,strain and doping, and produces peculiar cross-coupled effects, including magnetoresistance, magnetoelectricity andpiezoelectricity. Understanding and exploiting these effects is still one of the challenges in fundamental and materials sciences. Inrecent years, particular attention has been paid to transition metal oxides of the 5d series having simultaneously strong spin-orbitinteraction and sizable electronic correlation, and featuring a plethora of unconventional properties. However, a full exploration oftheir physical properties is far from being reached. Our proposal focuses on a combined experimental and theoreticalapproach to study relativistic Mott insulators, a novel family of correlated electron systems in the strong spin-orbitcoupling regime, which we aim to understand, engineer and, ultimately, control. We concentrate on theRuddlesden-Popper Sr Ir O iridate family to explore the regime where the energy scales of electronic correlation, bandwidth, n+1 n 3n+1spin-orbit interaction and ligand field are comparable. The n=1,2 and ∞ members of the family have already been synthesised anddisplay distinct properties: n=1 and 2 are relativistic Mott insulators, with ab-canted and c-axis collinear antiferromagnetic order,respectively, while n=∞ is a paramagnetic metal, implying a number of phase transitions for intermediate values of n. Unfortunately,large n (2<n<∞) RP iridates have not been synthesised yet, thus leaving an empty space for the advancement of knowledge, seeFigure 1. We aim to fill this void by artificially fabricating n>2 compounds as superlattices formed by n unit cells of SrIrO and a SrO 3layer and carrying out in-depth theoretical and experimental investigations to obtain a full understanding of the physics at play.Finally, we will attempt the electrical control of their transport and magnetic properties via strain by interfacing them withferroelectric oxides either in form or substrates or in artificial superlattices. Indeed, the combination of large magnetoresistance andthe aim to electrically control spin-flop transitions makes iridium oxides appealing for applications in oxide spintronics. Meanwhile, we plan to build up a durable research team of young scientists with international experience and complementaryexpertise in experimental and theoretical condensed matter physics.