原子大小(半徑)漸變型鍊金師贗勢之試作與測試

Trial implementation and tests of atomic-size-varying type alchemist pseudopotentials

黃振維(Zhen-Wei Huang)

指導教授 ： 李明憲

淡江大學/理學院/物理學系碩士班/碩士(2018年)

https://doi.org/10.6846/TKU.2018.00971

摘要

本論文藉由修改開源pseudopotential產生器OPIUM，使其可以產生鍊金師贗勢。鍊金師贗勢方法由李明憲老師提出，將兩元素之贗化波函數漸變，隨著波函數漸變也將本徵值線性漸變，如此可以做到將兩元素原子大小漸變。原子大小漸變鍊金師贗勢測試結果良好，可以做到晶胞大小線性漸變。獲得良好的測試結果後便使用鍊金師贗勢方法討論為何矽沒有平面結構的議題。鍊金師贗勢方法很好的模擬大小漸變的過程(符合超晶胞的晶胞邊長)，對於矽比碳大因此沒有平面結構的這個論點，給予支持的證據。並在此議題的測試中，有較VCA方法更好的超晶胞模擬的表現。鍊金師贗勢方法可以應用在物性研究中認為是大小效應造成物性變化的論點，給予證明或予以反證。鍊金師贗勢方法沒有VCA方法在模擬原子比例接近時，有巨大誤差的缺點，在未來的發展，具有取代VCA成為更好的晶體近似方法的潛力。

關鍵字

贗勢 ； 虛擬晶體近似法 ； 鍊金術 ； 石墨烯 ； 平面結構

並列摘要

We modify the open source of pseudopotential generator which is called OPIUM.We made the code which can produce alchemist pseudopotential in this thesis。Alchemist pseudopotential method is proposed by my advisor professor Ming-Hsien Lee.It is a way to vary in size from one atom to another by changing pseudo wave function and mixing eigenvalue linearly.Atomic-size-varying type alchemist pseudopotential can linearly vary the lattice constant in our test.We use alchemist pseudopotential to discuss the reason why silicon can not have plane structure after we have excellent result of test.Alchemist pseudopotential method simulate the process of size varing(lattice constant are correspond with super cell),so alchemist pseudopotential can support the argument that the silicon can not construct the plane structure because the size of silicon is larger than that of carbon.In this case Alchemist pseudopotential have better simulation of super cell than VCA.Alchemist pseudopotential can apply to recognize the size whether it causes physical properties changing.Alchemist pseudopotential have potential to replace VCA because it doesn’t make huge misteak in half mixing like VCA does.

並列關鍵字

Pseudopotential ； alchemical ； graphene ； plane structure

參考文獻

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