Creating unconventional metals

August 21, 2008

The semiconductor silicon and the ferromagnet iron are the basis for much of mankind's technology, used in everything from computers to electric motors. In this week's issue of the journal Nature (August 21st) an international group of scientists, including academic and industrial researchers from the UK, USA and Lesotho, report that they have combined these elements with a small amount of another common metal, manganese, to create a new material which is neither a magnet nor an ordinary semiconductor. The paper goes on to show how a small magnetic field can be used to switch ordinary semiconducting behaviour (such as that seen in the electronic-grade silicon which is used to make transistors) back on.

The new material exists in a quantum halfway house between magnet and semiconductor - in the same way that much more complex materials such as ceramics which exhibit high temperature superconductivity exist in quantum halfway houses between metals and magnetic insulators. The research is of fundamental importance because it demonstrates, for the first time, a simple recipe for reaching this halfway house, whilst also suggesting new mechanisms for controlling electrical currents and magnetism in semiconductor devices.

Professor J.F. DiTusa of Louisiana State University and a co-author of the paper said: "It's amazing that something which was thought to exist theoretically in mathematical physics could actually be found in an alloy which was simply formed by melting together a few common elements."

Professor Gabriel Aeppli of UCL (University College London), another member of the research team and Director of the London Centre for Nanotechnology, added: "It might be possible to see similar effects in devices made using materials and methods found in laser pointers. This would put what we've seen firmly in the realm of that which can easily be achieved using current technologies."

The first author of the paper, Dr. N. Manyala of the National University of Lesotho, said: "We are looking forward to investigating whether we can see these effects using thin layers of the same materials deposited directly on the silicon wafers. These wafers are the same as those used by mass market electronics manufacturers as the basis for integrated circuits." Dr. Ramirez, who is now with LGS-Bell Labs Innovations echoed this thought, noting that, "with the end of Moore's law in sight, mechanisms for controlling and understanding possible new information bits such as spins in solids are actively being sought after."

University College London

---

---

	The Essential Guide to Semiconductors by Jim Turley (Author) The Essential Guide to Semiconductors is a complete guide to thebusiness and technology of semiconductor design and manufacturing.Conceptual enough for laypeople and nontechnical investors, yet detailedenough for technical professionals, Jim Turley explains exactly howsilicon chips are designed and built, illuminates key markets andopportunities, and shows how the entire industry "fits together."
	Semiconductors 101: The TextVook by Vook Learn all about semiconductors in this eBook. "Semiconductors 101" presents what you need to know in an easy-to-digest format. This TextVook contains 4,000 words written and curated by Ivy League graduates, and stars Dr. Vook, Ph.D., a smart professor who explains everything you need to know. Whether you're interested in semiconductors for fun or brushing up on a course you took years ago, you will advance your knowledge. You will be able to read these 8 chapters: -Introduction -Semiconductor Basics -PN Junctions -PN Junction Under Bias -BJT -MOS Capacitor -MOSFET -Looking Forward
	Semiconductor Device Fundamentals by Robert F. Pierret (Author) Although roughly a half-century old, the field of study associated with semiconductor devices continues to be dynamic and exciting. New and improved devices are being developed at an almost frantic pace. While the number of devices in complex integrated circuits increases and the size of chips decreases, semiconductor properties are now being engineered to fit design specifications. Semiconductor Device Fundamentals serves as an excellent introduction to this fascinating field. Based in part on the Modular Series on Solid State Devices, this textbook explains the basic terminology, models, properties, and concepts associated with semiconductors and semiconductor devices. The book provides detailed insight into the internal workings of "building block" device structures and systematically...
	Fundamentals of Semiconductors: Physics and Materials Properties (Graduate Texts in Physics) by Peter Y. Yu (Author), Manuel Cardona (Author) Excellent bridge between general solid-state physics textbook and research articles packed with providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors "The most striking feature of the book is its modern outlook ... provides a wonderful foundation. The most wonderful feature is its efficient style of exposition ... an excellent book." Physics Today "Presents the theoretical derivations carefully and in detail and gives thorough discussions of the experimental results it presents. This makes it an excellent textbook both for learners and for more experienced researchers wishing to check facts. I have enjoyed reading it and strongly recommend it as a text for anyone working with semiconductors … I know of no better text …...
	Physics of Semiconductor Devices by Simon M. Sze (Author), Kwok K. Ng (Author) The Third Edition of the standard textbook and reference in the field of semiconductor devicesThis classic book has set the standard for advanced study and reference in the semiconductor device field. Now completely updated and reorganized to reflect the tremendous advances in device concepts and performance, this Third Edition remains the most detailed and exhaustive single source of information on the most important semiconductor devices. It gives readers immediate access to detailed descriptions of the underlying physics and performance characteristics of all major bipolar, field-effect, microwave, photonic, and sensor devices.Designed for graduate textbook adoptions and reference needs, this new edition includes:A complete update of the latest developmentsNew devices such as...
	Chips and Change: How Crisis Reshapes the Semiconductor Industry by Clair Brown (Author), Greg Linden (Author) For decades the semiconductor industry has been a driver of global economic growth and social change. Semiconductors, particularly the microchips essential to most electronic devices, have transformed computing, communications, entertainment, and industry. In Chips and Change, Clair Brown and Greg Linden trace the industry over more than twenty years through eight technical and competitive crises that forced it to adapt in order to continue its exponential rate of improved chip performance. The industry's changes have in turn shifted the basis on which firms hold or gain global competitive advantage.These eight interrelated crises do not have tidy beginnings and...
	Semiconductor Physics And Devices: Basic Principles by Donald A. Neamen (Author) With its strong pedagogy, superior readability, and thorough examination of the physics of semiconductor material, Semiconductor Physics and Devices, 4/e provides a basis for understanding the characteristics, operation, and limitations of semiconductor devices. Neamen's Semiconductor Physics and Devices deals with the electrical properties and characteristics of semiconductor materials and devices. The goal of this book is to bring together quantum mechanics, the quantum theory of solids, semiconductor material physics, and semiconductor device physics in a clear and understandable way.
	The Story of Semiconductors by John W. Orton (Author) The book provides an overview of the fascinating spectrum of semiconductor physics, devices and applications, presented from a historical perspective. It covers the development of the subject from its inception in the early nineteenth century to the recent millennium. Written in a lively, informal style, it emphasizes the interaction between pure scientific push and commercial pull, on the one hand, and between basic physics, materials, and devices, on the other. It also sets the various device developments in the context of systems requirements and explains how such developments met wide-ranging consumer demands. It is written so as to appeal to students at all levels in physics, electrical engineering, and materials science, to teachers, lecturers, and professionals working in the...
	Semiconductor Manufacturing Technology by Michael Quirk (Author), Julian Serda (Author) In this book, Quirk and Serda introduce the terminology, concepts, processes, products, and equipment commonly used in the manufacture of ultra large scale integrated (ULSI) semiconductors. The book provides helpful, up-to-date technical information about semiconductor manufacturing and strikes an effective balance between the process and equipment technology found in wafer fabrications. Topics include copper interconnect; dual damascene additive process for metallization; deep UV sub-micron photolithography (.18 micron and below); low-k dielectric processing; chemical mechanical planarization; a comprehensive model of manufacturing process; chemical-mechanical polish (CMP); and maintenance and troubleshooting. For practicing semiconductor manufacturing technicians or those interested...
	Handbook on Physical Properties of Semiconductors, 3 volume set by Sadao Adachi (Author) The aim of this 3-volume reference is to present accurate, reliable and up-to-date information on the physical properties of group IV elemental semiconductors (Vol. 1), III-V compound semiconductors (Vol. 2) and II-VI semiconductors (Vol. 3). The data on the physical properties of each material are organized in the same way throughout these volumes to facilitate searching for information. The physical properties considered in these volumes can be classified into 12 groups: structural properties; -thermal properties; -elastic properties; -phonons and lattice vibronic properties; -collective effects and related properties; -energy-band structure: energy-band gaps; -energy-band structure: electron and hole effective mass; -electronic deformation potential; -electron affinity...