一种光电子能谱费米面拼接方法
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摘要
光电子能谱技术可以直接探测材料的费米面结构,是研究材料电子结构的重要实验手段。由于光源光子能量、探测器探测角度范围以及材料本身的因素,光电子能谱技术一次只能探测布里渊区一个位置区域的费米面信息。本文提出一种将不同位置区域测量的费米面拼接起来的方法:首先根据费米面结构特征对费米面进行配准,以其中一个费米面为基准,求出仿射变换矩阵,然后对费米面进行二值化,求出测量区域轮廓,最后以到测量区域轮廓的距离作为权重将两费米面重叠区域按照像素进行拼接融合,非重叠区域保持不变。与直接相加相比,这种方法可以有效融合重叠区域,消除边界处的不连续性,获取完整费米面,提高数据质量。本文提到的方法可以从数据处理的角度弥补角分辨光电子能谱在探测范围上的不足。
Photoemission spectroscopy can directly probe the Fermi surface and serves as a key experimental tool to investigate electronic structure of materials.Considering limitation of photon energy,detector angle and lattice constant of material,angle-resolved photoemission spectroscopy can only detect one specific portion of the Fermi surface once.This paper presents a method of stitching the Fermi surfaces of the same sample measured in different momentum space.Firstly,the Fermi surfaces are registered according to the structural features and the affine transformation matrix is obtained based on one of the Fermi surfaces.Then the Fermi surface is binarized to obtain the boundary contour.Finally,the overlapping areas of the two Fermi surfaces are fused taking the distance from the pixel to Fermi surface boundary contour as the weight factor.The un-overlapping regions remain unchanged.Compared to adding the two Fermi surfaces directly,this method can eliminate the dis-continuity at the boundary effectively and merge the Fermi surfaces finely without degrading of data quality.This method is a compensation of the limited probing ability of angle-resolved photoemission spectroscopy from the aspect of data sets processing and analyzing.
Photoemission spectroscopy can directly probe the Fermi surface and serves as a key experimental tool to investigate electronic structure of materials.Considering limitation of photon energy,detector angle and lattice constant of material,angle-resolved photoemission spectroscopy can only detect one specific portion of the Fermi surface once.This paper presents a method of stitching the Fermi surfaces of the same sample measured in different momentum space.Firstly,the Fermi surfaces are registered according to the structural features and the affine transformation matrix is obtained based on one of the Fermi surfaces.Then the Fermi surface is binarized to obtain the boundary contour.Finally,the overlapping areas of the two Fermi surfaces are fused taking the distance from the pixel to Fermi surface boundary contour as the weight factor.The un-overlapping regions remain unchanged.Compared to adding the two Fermi surfaces directly,this method can eliminate the dis-continuity at the boundary effectively and merge the Fermi surfaces finely without degrading of data quality.This method is a compensation of the limited probing ability of angle-resolved photoemission spectroscopy from the aspect of data sets processing and analyzing.
引文
[1]黄昆,韩汝琦.固体物理学[M].北京:高等教育出版社,2010:213-223.
[2]XIA Y,QIAN D,WRAY L,et al.Fermi surface topology and low-lying quasiparticle dynamics of parent Fe1txTe=Se Superconductor[J].Physical Review Letters.103,037002(2009).
[3]MENG J Q,LIU G D,ZHANG W T,et al.Coexistence of Fermi arcs and Fermi pockets in a high-Tc copper oxide superconductor[J].Nature.462,335-338(2009).
[4]MOU D X,SAPKOTA A,H.-H.Kung,et al.Discovery of an unconventional charge density wave at the surface of K0.9Mo6O17[J].Physical Review Letters.116,196401(2016).
[5]Stefan Hufner.,Photo Electron Spectroscopy[M].Springer.(2003).
[6]LIU G D,Wang G L,ZHU Y,et al.Development of a vacuum ultraviolet laser-based angle-resolved photoemission system with a superhigh energy resolution better than 1meV[J].Rev.Sci.Instrum.79,023105(2008).
[7]贾小文.角分辨光电子能谱对重费米子超导体CeCoIn5和铁基超导体Fe(SexTe1-x)的研究[D].北京:中国科学院物理研究所,2011.
[8]贾小文.Igor Pro实用教程[M].北京:清华大学出版社(2018).
[9]谢凤英,赵丹培,李露,等,数字图像处理及应用[M].北京:电子工业出版社(2014).
[2]XIA Y,QIAN D,WRAY L,et al.Fermi surface topology and low-lying quasiparticle dynamics of parent Fe1txTe=Se Superconductor[J].Physical Review Letters.103,037002(2009).
[3]MENG J Q,LIU G D,ZHANG W T,et al.Coexistence of Fermi arcs and Fermi pockets in a high-Tc copper oxide superconductor[J].Nature.462,335-338(2009).
[4]MOU D X,SAPKOTA A,H.-H.Kung,et al.Discovery of an unconventional charge density wave at the surface of K0.9Mo6O17[J].Physical Review Letters.116,196401(2016).
[5]Stefan Hufner.,Photo Electron Spectroscopy[M].Springer.(2003).
[6]LIU G D,Wang G L,ZHU Y,et al.Development of a vacuum ultraviolet laser-based angle-resolved photoemission system with a superhigh energy resolution better than 1meV[J].Rev.Sci.Instrum.79,023105(2008).
[7]贾小文.角分辨光电子能谱对重费米子超导体CeCoIn5和铁基超导体Fe(SexTe1-x)的研究[D].北京:中国科学院物理研究所,2011.
[8]贾小文.Igor Pro实用教程[M].北京:清华大学出版社(2018).
[9]谢凤英,赵丹培,李露,等,数字图像处理及应用[M].北京:电子工业出版社(2014).