1ST PRINCIPLES CALCULATION OF NATIVE DEFECT DENSITIES IN HG0.8CD0.2TE
1ST PRINCIPLES CALCULATION OF NATIVE DEFECT DENSITIES IN HG0.8CD0.2TE
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DOI：
10.1103/physrevb.50.1519
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发表时间：
1994-07-15
影响因子：
3.7
通讯作者：
SHER, A
中科院分区：
文献类型：
--
作者：
BERDING, MA;VANSCHILFGAARDE, M;SHER, A
我们使用一个准化学的形式主义，使本征点缺陷密度的Hg0.8Cd0.2Te的定量预测。采用自洽的第一性原理全势能线化muffin-tin轨道方法和局域密度近似（LDA）计算了电子对缺陷形成自由能的贡献。对LDA结果进行了梯度校正，以便可以绝对参考汞蒸气相的化学势。一个绿色函数方法的基础上的价力场加上一个点库仑模型被用来计算振动的缺陷自由能（能量和熵）的贡献。我们发现双受主汞空位是主要的缺陷，与以前的实验解释。碲反位也被发现是这种材料中的一个重要缺陷。低温空穴浓度的预测作为退火温度的函数，并与现有的实验进行比较。我们的预测的数量级与实验结果一致，差异可以归因于我们忽略的自由能的贡献或使用的固有反应常数的不准确性。对进一步的实验工作提出了建议。
We use a quasichemical formalism to make quantitative predictions of the native point defect densities in Hg0.8Cd0.2Te. The electronic contribution to the defect-formation free energy is calculated using the self-consistent first-principles full-potential linearized muffin-tin orbital method and the local-density approximation (LDA). A gradient correction is added to the LDA result so that absolute reference to the chemical potential of the mercury vapor phase can be made. A Green's function approach based on a valence force field plus a point Coulomb model is used to calculate the vibrational contributions to the defect free energy (both energy and entropy). We find the double acceptor mercury vacancy is the dominant defect, in agreement with previous interpretations of experiments. The tellurium antisite is also found to be an important defect in this material. Predictions of the low-temperature hole concentrations are made as a function of annealing temperature and compared with available experiments. The order of magnitude of our predictions agrees well with experimental results, and discrepancies can be attributed to contributions to the free energy that we have neglected or to inaccuracies in the intrinsic reaction constant used. Suggestions for further experimental work are made.