Title: DFT Investigations of Major Defects in Quartz Crystal: Implications for Luminescence and ESR Dosimetry and Dating Show Chinese title

Title: 石英晶体主要缺陷的DFT研究：对发光和电子顺磁共振剂量测定及测年的影响

Abstract: Quartz is extensively used for luminescence and ESR dosimetry as well as dating. These techniques use inherent defects introduced in quartz crystal during its crystallization in nature. The defect comprises both intrinsic as well as extrinsic defects. These defects give important luminescence properties to quartz but are not yet well understood from a theoretical perspective. Specifically, in case of luminescence dosimetry the nature of traps and their involvement in luminescence production is not exactly known. Thus, present work attempts to understand the basic physics of defects and their implication for luminescence and ESR techniques via Density Functional Theory (DFT) modelling. The work uses DFT to model the presence of some possible major impurities in quartz. Several interesting novel results are obtained that will have implications for ongoing research in Luminescence and ESR methods. The DFT modelling suggested that Oxygen deficiency in quartz crystal results in the formation of both electron and hole trapping centres. However, it is observed that these centres can be passivated by the introduction of charge compensating OH or H ions. Further, it is found that peroxy defects can be formed in the presence of either excess Oxygen or due to the absence of Silicon (Si4+), however, the nature of the traps formed in both cases is different. Besides these intrinsic defects, Al and Fe are the major impurities which are observed as defects in quartz. The modelling of these impurities suggested that negligible change in DOS is observed for Al defect and Fe generally forms a recombination centre or hole trap. In addition to these, there are several interesting first-time observations that are not reported and will be helpful for progressing luminescence and ESR dosimetry research. Show Chinese abstract

Abstract: 石英被广泛用于发光和电子顺磁共振（ESR）剂量测定以及年代测定。 这些技术利用了石英晶体在自然界结晶过程中引入的固有缺陷。 这些缺陷包括本征缺陷和非本征缺陷。 这些缺陷赋予石英重要的发光特性，但从理论角度来看尚未得到充分理解。 具体而言，在发光剂量测定的情况下，陷阱的性质及其在发光产生中的作用尚不清楚。 因此，目前的工作试图通过密度泛函理论（DFT）建模来理解缺陷的基本物理特性和它们对发光和ESR技术的影响。 这项工作使用DFT来模拟石英中一些可能的主要杂质的存在。 获得了几个有趣的新的结果，这将对正在进行的发光和ESR方法的研究产生影响。 DFT建模表明，石英晶体中的氧缺乏会导致电子和空穴捕获中心的形成。 然而，观察到这些中心可以通过电荷补偿的OH或H离子的引入而被钝化。 此外，发现过氧缺陷可以在存在过量氧或由于硅（Si4+）缺失的情况下形成，但在两种情况下形成的陷阱性质不同。 除了这些本征缺陷外，Al和Fe是石英中观察到的主要杂质。 这些杂质的建模表明，Al缺陷的DOS变化可以忽略不计，而Fe通常形成重组中心或空穴陷阱。 除此之外，还有几个首次观察到的现象未被报道，将有助于推动发光和ESR剂量测定研究的发展。