Schönhense G, Medjanik K, Chernov S, Kutnyakhov D, Fedchenko O, Ellguth M, Vasilyev D, Zaporozhchenko-Zymaková A, Panzer D, Oelsner A, Tusche C, Schönhense B, Braun J, Minár J, Ebert H, Viefhaus J, Wurth W, Elmers H J
Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55099 Mainz, Germany.
Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55099 Mainz, Germany.
Ultramicroscopy. 2017 Dec;183:19-29. doi: 10.1016/j.ultramic.2017.06.025. Epub 2017 Jul 6.
The combination of momentum microscopy (high resolution imaging of the Fourier plane) with an imaging spin filter has recently set a benchmark in k-resolution and spin-detection efficiency. Here we show that the degree of parallelization can be further increased by time-of-flight energy recording. On the quest towards maximum information (in earlier work termed "complete" photoemission experiment) we have studied the prototypical high-Z fcc metal iridium. Large partial bandgaps and strong spin-orbit interaction lead to a sequence of spin-polarized surface resonances. Soft X-rays give access to the 4D spectral density function ρ (E,k,k,k) weighted by the photoemission cross section. The Fermi surface and all other energy isosurfaces, Fermi velocity distribution v(k), electron or hole conductivity, effective mass and inner potential can be obtained from the multi-dimensional array ρ by simple algorithms. Polarized light reveals the linear and circular dichroism texture in a simple manner and an imaging spin filter exposes the spin texture. One-step photoemission calculations are in fair agreement with experiment. Comparison of the Bloch spectral function with photoemission calculations uncovers that the observed high spin polarization of photoelectrons from bulk bands originates from the photoemission step and is not present in the initial state.
动量显微镜（傅里叶平面的高分辨率成像）与成像自旋滤波器的结合最近在k分辨率和自旋检测效率方面树立了一个标杆。在这里我们表明，通过飞行时间能量记录可以进一步提高并行化程度。在追求最大信息（在早期工作中称为“完整”光电子发射实验）的过程中，我们研究了典型的高Z面心立方金属铱。大的部分带隙和强自旋轨道相互作用导致了一系列自旋极化表面共振。软X射线可以获取由光电子发射截面加权的四维光谱密度函数ρ（E，k，k，k）。费米面和所有其他能量等值面、费米速度分布v（k）、电子或空穴电导率、有效质量和内势可以通过简单算法从多维数组ρ中获得。偏振光以简单的方式揭示线性和圆二色性纹理，而成像自旋滤波器则揭示自旋纹理。单步光电子发射计算与实验结果相当吻合。将布洛赫光谱函数与光电子发射计算进行比较发现，从体带中观察到的光电子的高自旋极化源于光电子发射步骤，而在初始状态中不存在。
