Quantum Unfolding: A program for unfolding electronic energy bands of materials

Abstract
We present Quantum Unfolding, a Fortran90 program for unfolding first-principles electronic energy bands. It unfolds energy bands accurately by handling the Fourier components of Bloch wavefunctions, which are reconstructed from Wannier functions from Wannier90. Due to the wide application of Wannier90 package and the possibility of focusing only on the most important energy bands, the present code works very conveniently.

Title of program: Quantum Unfolding
Catalogue Id: AEVF_v1_0

Nature of problem
The Brillouin zone of a supercell is smaller than that of a primary cell. It makes the supercell energy bands more crowded. The crowded energy bands are outright difficult, if not impossible, to be compared with experimental results directly. Besides, the intra-supercell translation symmetries are hidden in the supercell band structure calculations. In order to compare with experiments and catch the hidden symmetries, we have to unfold the supercell energy bands into the corresponding primary-ce ...

Versions of this program held in the CPC repository in Mendeley Data
AEVF_v1_0; Quantum Unfolding; 10.1016/j.cpc.2014.12.009

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)

**摘要**
本研究提出了Quantum Unfolding，一款用于展开第一性原理电子能带的Fortran90程序。该程序通过处理布洛赫波函数（Bloch wavefunctions）的傅里叶分量来精准实现能带展开，而布洛赫波函数可由Wannier90工具包生成的瓦尼尔函数（Wannier functions）重构得到。鉴于Wannier90工具包应用广泛，且本程序支持仅聚焦于关键能带，因此使用起来极为便捷。

程序名称：Quantum Unfolding
目录编号：AEVF_v1_0

**问题本质**
超胞的布里渊区（Brillouin zone）小于原胞，这会导致超胞能带更为密集。这类密集排布的能带即便并非完全无法，也极难直接与实验结果进行比对。此外，超胞能带结构计算中，超胞内平移对称性会被隐藏。为了能够与实验结果比对并挖掘出隐藏的对称性，我们需要将超胞能带展开至对应原胞的布里渊区中……

**Mendeley Data中CPC库存储的该程序版本**
AEVF_v1_0; Quantum Unfolding; 10.1016/j.cpc.2014.12.009

本程序源自贝尔法斯特女王大学托管的CPC程序库（1969-2018年）