Title: Molecular Beam Epitaxial Growth of Spintronic Materials 

Speaker: Prof. Chris Palmstrom (Electrical and Computer Engineering and Materials, University of California, Santa Barbara)   

Time: OCT. 23, 2015 10:00AM 

Venue: No. 101 Meeting Room, IOS, CAS 

Abstract: The spin dependent transport across ferromagnet/semiconductor interfaces depends critically on their structure and electronic properties. Interfacial reactions, the formation of non-magnetic interlayers, and conductivity mismatch have been attributed to low spin injection efficiency. In the case of Fe3Ga/GaAs (001) interfaces, the interface reconstruction was found to depend on the GaAs (001) surface reconstruction and the Fe3Ga growth conditions. Record high spin accumulation at Co2MnSi Heusler compound/GaAs (001) interfaces in lateral spin transport device structures have been measured. Using a combination of molecular beam epitaxy and in-situ scanning tunneling microscopy and x-ray photoelectron spectroscopy, we have investigated the interface formation and growth mechanisms. Ab-initio theory and ex-situ transmission electron microscopy studies have been used to corroborate the Heusler compound/semiconductor interfacial atomic structure. This presentation will emphasize the progress in the understanding of the atomic scale structure of epitaxial magnetic metal/III-V semiconductor heterostructures interface and its influence on the magnetic and spin transport properties.

Biography：Professor Chris Palmstrom, one of the world's leading researchers of electronic materials, joined the ECE faculty at UCSB in the Fall of '07. Born in Norway, Palmstrom received his PhD in Electrical and Electronic Engineering from the University of Leeds (England) in 1979. After five years of research on semiconductor materials and contact technologies at Cornell, he joined Bellcore in 1985. There, he did groundbreaking research on semiconductor surfaces, semiconductor doping, polymer/polymer diffusion and the molecular beam epitaxial growth of metal/semiconductor heterostructures. In 1994, Dr. Palmstrom went to the University of Minnesota, where he soon became a leading researcher in several fields, including new spintronic materials that combine the functions of electronic and magnetic manipulation and storage on information. Professor Palmstrom fits well into UCSB's research programs where he already has significant collaborations with Professors Gossard, Brown, Rodwell, Stemmer, and Van der Walle. With the addition of Palmstrom, UCSB can ensure the continued success of our strong activities related to molecular beam epitaxy development of new nanoscopically controlled materials for future electronic and optical devices and systems.