Low Temperature Nuclear Spin Relaxation and the Structure and Dynamics of Defects in Materials

小行星9305344 该项目将为量子固体和薄膜以及材料缺陷的联合理论和低温实验研究提供支持。 理论和脉冲核磁共振研究将进行分子氢和氘和稀有气体原子物理吸附在氧化镁，氮化硼和硅薄膜。 这些分子和原子也将作为非磁性宿主中的基质隔离物种和在低温核磁共振（NMR）金刚石对顶砧单元中的高压下进行研究。 多个自旋回波独特的吸附物种将被用来检查动力学和相变在高密度和有限的维度。 一个密切相关的努力将检查氢和氘在非晶半导体薄膜的条件下，光诱导的亚稳态变化的材料的电子特性发生。 理论上的努力将包括第一原理分子动力学模拟含有各种掺杂剂的非晶硅的大型超级电池。 该项目将为量子固体和薄膜以及材料缺陷的联合理论和低温实验研究提供支持。 理论和脉冲核磁共振研究将进行分子氢和氘和稀有气体原子物理吸附在氧化镁，氮化硼和硅薄膜。 这些材料也将在高压下进行检查。 该研究涉及基本主题以及与材料缺陷相关的技术重要主题，以及这些缺陷在确定材料性能中的作用。 例如，将研究掺杂各种原子的非晶半导体，以了解更多关于用于光电导太阳能电池的这些材料的特性。 该研究将揭示目前限制其效率和实用性的光电池的亚稳态特性。 ***

9305344 Norberg This project will provide support for a joint theoretical and low temperature experimental study of quantum solids and films and of defects in materials. Theoretical and pulsed nuclear magnetic resonance investigations will be carried out on molecular hydrogen and deuterium and rare gas atoms physisorbed as thin films on magnesium oxide, boron nitride, and silicon. These molecules and atoms will also be studied as matrix-isolated species in non- magnetic hosts and at high pressures in a cryogenic nuclear magnetic resonance (NMR) diamond anvil cell. Multiple spin echoes unique to adsorbed species will be used to examine dynamics and phase transitions at high densities and under restricted dimensionality. A closely related effort will examine hydrogen and deuterium in amorphous semiconducting films under conditions where light-induced metastable changes in the electronic properties of the materials occur. The theoretical effort will include first principles molecular dynamics simulations on large supercells of amorphous silicon containing various dopants. %%% This project will provide support for a joint theoretical and low temperature experimental study of quantum solids and films and of defects in materials. Theoretical and pulsed nuclear magnetic resonance investigations will be carried out on molecular hydrogen and deuterium and rare gas atoms physisorbed as thin films on magnesium oxide, boron nitride, and silicon. These materials will also be examined at high pressures. The research involves fundamental topics as well as technologically important subjects related to defects in materials and the role these defects play in determining materials properties. For example, amorphous semiconductors doped with various atoms will be investigated to learn more about the properties of these materials which are used in photoconducting solar cells. The research should shed light on the metastable properties of the photocells which at present li mit their efficiency and practical utility. ***