Spintronics meets Nanomechanics

Jour Fixe talk by Gianluca Rastelli on December 11, 2014

“The paradox is only a conflict between reality and your feeling of what reality ought to be.” This quote by Richard Feynman can to some extent be seen as basis of Gianluca Rastelli´s research on quantum mechanics.  

In short, quantum mechanics is the study of the matter (atoms) and radiation starting from the atomic (microscopic) level. But what is its benefit? “Quantum mechanics offers a complex and fascinating worldview”, says the physicist. “It represents a unified description of the laws of nature. Its principles and concepts are fundamental and important in Chemistry, Biology, electronic Engineering, Informatics, etc. Although its discovery is dating back to the beginning of the past century, quantum mechanics is showing only recently its outstanding potential applications (nanosciences and quantum information). The investigation of these fundamental issues will be useful for many future technologies, such as for the development of new nanoscale optical/electronic devices or perhaps even for the building of quantum computers and quantum communication.”

The investigation of quantum physics began in the early 20th century, when some experiments produced results which could not be explained by classical physics - the science developed by Galileo Galilei, Isaac Newton, James Maxwell, etc. which aimed at explaining physical objects larger than atoms and molecules.

Having two approaches, the classical physics vs. quantum mechanics, produced open questions: Where is the border between the microscopic, purely quantum realm and our macroscopic world? Can we observe quantum phenomena in macroscopic systems (composed by a huge number of atoms)? What about quantum experiments with objects large enough to be visible to the naked eye?

Gianluca Rastelli has focused his research on quantum effects in solid macroscopic objects, especially on Nano-Electro-Mechanical Systems (NEMS). These are nano-electronic devices with a mechanical resonator. They can be applied in ultra-sensitive detectors for mass, forces at the microscopic scales and for charge and spin detection. The first solid object to be put into a quantum state was a mechanical drum. It was succeeded to create such a large object into a quantum superposition state of moving (excited energy state) and not moving (ground state). The mechanical drum was formed by N=1000000 (millions) of atoms.

The physicist explained: “Spintronics is an emerging technology exploiting both the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices.” He aims at analyzing how to drive the carbon resonator in quantum regime, how to control its quantum states, and how to detect it. His objective is the control of carbon nano-mechanical resonators using spin-dependent quantum transport.