INTRODUCTION TO SPINTRONICS.pptVIP

230% with sputtering deposition * Non volatile, instant-on computers * DRAM stores one bit in only one capacitor and transistor, very dense but very power hungry because capacitor loses charge, must be frequently refreshed SRAM stores one bit in six transistors, faster than DRAM but less dense * Rashba effect – consequence of spin orbit interaction, proportional to electric field in a structure with inversion asymmetry * Ideally, each Mn dopant atom represents an acceptor that introduces a local spin and a hole carrier * “The crystalline quality, surface topography, and thermal stability of the films indicate the possibility of growing epitaxial Ge on top of Mn5Ge3 so that epitaxial trilayers or ‘spin valves’ and perhaps even multilayer structures can be fabricated for spintronics research and applications.” * 2006 Princeton, A. Yazdani et al. used STM to carefully place individual atoms on GaAs substrate Swarms of bees, spin polarized currents * INTRODUCTION TO SPINTRONICS Josh Schaefferkoetter February 27, 2007 INTRODUCTION Conventional electronic devices ignore the spin property and rely strictly on the transport of the electrical charge of electrons Adding the spin degree of freedom provides new effects, new capabilities and new functionalities FUTURE DEMANDS Moore’s Law states that the number of transistors on a silicon chip will roughly double every eighteen months By 2008, it is projected that the width of the electrodes in a microprocessor will be 45nm across As electronic devices become smaller, quantum properties of the wavelike nature of electrons are no longer negligible Spintronic devices offer the possibility of enhanced functionality, higher speed, and reduced power consumption ADVANTAGES OF SPIN Information is stored into spin as one of two possible orientations Spin lifetime is relatively long, on the order of nanoseconds Spin currents can be manipulated Spin devices may combine logic and storage functionality eliminating the need for sepa