高压与掺杂对KDP晶体能带结构的影响

Influence of High-pressure and Doping on the Band Structure of KDP Crystal

构建了高压条件下KDP晶体的原子结构模型和掺杂有Li+、Na+、Rb+、Cs+、Be2+、Mg2+、Ca2+、Cr3+、Co2+、Cu2+、Al3+、La3+等12种阳离子的KDP晶体超级原胞结构模型,采用第一性原理计算了高压下的KDP晶体的能带结构和态密度,研究了替位式掺杂的形成能以及不同掺杂离子对电子结构的影响。结果表明:KDP晶体的带隙宽度随着压强的增加呈线性增长趋势;Co2+、Cu2+、La3+等重金属离子具有较低的掺杂形成能而易于形成替位式掺杂;碱金属离子掺杂后其带隙比二价离子和三价离子替位掺杂情形大得多,且随原子序数增大而增大。文章还依据能带理论构建了材料的电导率和热导率与带隙的关联式,分析讨论了高压和掺杂对KDP晶体热导率和激光损伤的影响。

The atomic structure model of the KDP crystal upon high-pressure is built. The super cell of KDP crystal is constructed, which is doped by Li ＋ , Na ＋ , Rb ＋ , Cs ＋ , Be2 ＋ , Mg2 ＋ , Ca2 ＋ , Cr3 ＋ , Co2 ＋ , Cu2 ＋ , A13＋ , La3 ＋ individually. The band structure and density of states of KDP single crystals were calculated by the first principal. The formation and electrical structure of KDP crystal under this displacement dope were studied. The results indicated that the band-gap of KDP crystal becomes wider with the rise of the pressure. Heavy metal ions such as Co2 ＋ ,Cu2 ＋ ,La3 ＋ are easier to take shape of displacement dope because of their low formation energy. The band-gap of KDP crystal doped by alkali metal is much wider than that of the divalet ions and trivalent ions. The band gap grows up With the increasing atomic number. An equation has been built, which connects electro-conductibility and thermal conductivity of material. Finally, this paper put emphasis on the discussion of the laser damage caused by high-pressure and dope.