Mesoscopic Spin Magnetism

Mesoscopic magnetism and quantum chaos

All seven physics STAIRSTEP students and 15 undergraduate students have participated to a talk about the orbital magnetic susceptibility of electrons in a rectangular box. Mesoscopic systems, such as small metal particles and quantum dots, exhibit many novel properties due to the coherent effect and finite-size quantization. In the mesoscopic regime, magnetic properties are sensitive to whether...

Spin liquids and frustrated magnetism

Quantum Magnetism Control Spin Interactions

Scientists have achieved the ultimate speed limit of the control of spins in a solid state magnetic material. The rise of the digital information era posed a daunting challenge to develop ever faster and smaller devices for data storage and processing. An approach which relies on the magnetic moment of electrons (i.e. the spin) rather than the charge, has recently turned into major research fie...

Spin tunnelling in mesoscopic systems

Abstract. We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied magnetic field, vanishing completely at special points in the space of magnetic fields, known as diabolical points. This phenomen...

Integrability and Disorder in Mesoscopic Systems: Application to Orbital Magnetism

We present a semiclassical theory of weak disorder effects in small structures and apply it to the magnetic response of non–interacting electrons confined in integrable geometries. We discuss the various averaging procedures describing different experimental situations in terms of one– and two–particle Green functions. We demonstrate that the anomalously large zero-field susceptibility characte...