9319404 Maradudin This proposal concerns several aspects of materials theory; anharmonic interactions in crystals, optical properties of solids and the doping of semiconductor systems. (1a) First principles calculations of the anharmonic force constants and phonon linewidths in Al and Cu will be performed. (1b) Calculations of the ultrasonic attenuation in Si will be attempted. (2a) The nonreciprocal photonic band structure effects in n-type semiconductors in magnetic fields will be investigated. (2b) Light localization in infinite periodic arrays of dielectric rods will be studied. (3a) The stability of ternary alloys of III-V semiconductors deposited on semiconductor substrates will be examined from the point of view of elastic energy effects. (3b) The equilibrium doping of boron in silicon will be studied taking special account of vibrational contributions to the free energy. %%% This proposal concerns the calculation of a wide variety of materials properties in specific systems. It is divided into three broad areas. The first concerns vibrational properties of metals and semiconductors - specifically how sound is attenuated in silicon and how harmonic are the vibrations in simple metals. The second involves how light may be trapped or may be manipulated in carefully constructed periodic materials. The third studies the stability of semiconductor alloys that are adsorbed on other semiconductors and why it is difficult to dope silicon with boron (a useful dopant if it could be achieved). ***
