Spintronics: electron spin coherence, entanglement, and transport

TL;DR

This paper presents theoretical insights into spin coherence, entanglement, and transport in spintronics, addressing fundamental mechanisms and proposing models for quantum computing and spin-polarized transport.

Contribution

It provides detailed quantitative theories on spin relaxation, coherence, entanglement, and transport, resolving longstanding puzzles and assessing quantum dot quantum computer architectures.

Findings

Fast spin relaxation in aluminum explained

Quantitative analysis of spin entanglement in double quantum dots

Characterization of spin-polarized transport via Andreev reflection

Abstract

Prospect of building spintronic devices in which electron spins store and transport information has attracted strong attention in recent years. Here we present some of our representative theoretical results on three fundamental aspects of spintronics: spin coherence, spin entanglement, and spin transport. In particular, we discuss our detailed quantitative theory for spin relaxation and coherence in electronic materials, resolving in the process a long-standing puzzle of why spin relaxation is extremely fast in Al (compared with other simple metals). In the study of spin entanglement, we consider two electrons in a coupled GaAs double-quantum-dot structure and explore the Hilbert space of the double dot. The specific goal is to critically assess the quantitative aspects of the proposed spin-based quantum dot quantum computer architecture. Furthermore, we discuss our theory of spin-polarized transport across a semiconductor-metal interface. In particular, we study Andreev reflection, which enables us to quantify the degree of carrier spin polarization and the strength of interfacial scattering.