Thermodynamics and Electrodynamics of Unusual Narrow - gap Semiconductors Albert Migliori , Timothy W . Darling

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL) that has led to a fully funded DOE program to continue this work. The project was directed toward exploring the Ettingshausen effect. which is the direct extension of the familiar Peltier-effect refrigerator (the process used in popular coolers that run off automotive electrical power) in which a magnetic field is used to enhance refrigeration effects at temperatures well below room temperature. Such refrigeration processes are all-solid-state and are of potentially great commercial importance, but essentially no work has been done since the early 1970s. Using modem experimental and theoretical techniques, we have advanced the state-of-the-art significantly, laying the groundwork for commercial cryogenic solid-state refrigeration. Background and Research Objectives materials in which a strong magnetic field is present, and to indicate new directions in this old and extensively studied area of electronic transport in solids. The basic physical effects that describe heat transport by charge carriers in solids are the Peltier effect and the Ettingshausen effect. The Peltier effect, governing all modern thermoelectric coolers, is a thermal transport process requiring no magnetic field in which a thermal gradient is created parallel to an applied electric current. The Ettingshausen effect, a somewhat obscure but powerful refrigeration process, is a thermal transport process in which a thermal gradient is created perpendicular to an applied electric current and both these are perpendicular to an applied magnetic field. Because of the extensive literature on these processes and because of the detailed complexity of the new approaches developed at our Laboratory, we will attempt only to present an accurate but simple overview. in electronic refrigerators. This appreciation was inspired by their large thermoelectric power (S) and low thermal conductivity. All present-day devices (Peltier coolers), however, use doped B4Te3 and operate near room temperature and without a magnetic field. The Sb alloys Our intent in this section is to provide a basic review of thermoelectric cooling in For some period of time, there has been an established interest in Bi,-,Sb, alloys for use