HIGH-PRESSURE SYNTHESIS, CHARACTERIZATION, AND TUNING OF SOLID STATE MATERIALS

The synthesis, characterization, and tuning of solid state materials by means of high-pressure techniques is reviewed from the perspective of a solid state chemist. Because pressure can affect significant changes in reaction equilibria, it is a useful tool for the synthesis of novel and metastable materials. Several different examples ranging from the behavior of carbon under pressure to oxide materials and intermetallic compounds are presented to illustrate the breadth of opportunities in this area. Pressure allows precise tuning of a fundamental parameter, interatomic distance, which controls the electronic structure and virtually all the interatomic interactions that determine materials properties. With pressure tuning, properties can often be more rapidly and cleanly optimized than with chemical tuning, which necessitates the synthesis of a large number of different materials and can induce disorder, phase separation, and other undesirable effects. Pressure tuning is therefore a useful tool in the search for new solid state materials with enhanced properties such thermoelectric materials and intermetallic structural materials.