Imaging properties of hemispherical electrostatic energy analyzers for high resolution momentum microscopy

Tusche, Christian; Chen, Ying-Jiun; Schneider, Claus M.; Kirschner, J.

doi:10.1016/j.ultramic.2019.112815

Cited by 48 publications

(57 citation statements)

References 22 publications

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“…In the latter case the transmission of the analyzer entrance lens increases by N, in addition to the parallel recording of N slices (Scho ¨nhense et al, 2020b). In comparison with hemispherebased momentum microscopes (Tusche et al, 2015(Tusche et al, , 2019 the gain factor is just given by the number of resolved time slices N. A prototype instrument with a large hemispherical analyzer (225 mm path radius) will be installed at Diamond [beamline I09 (Lee & Duncan, 2018)].…”

Section: Discussionmentioning

confidence: 99%

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Schönhense¹,

Medjanik²,

Fedchenko³

et al. 2021

J Synchrotron Radiat

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The small time gaps of synchrotron radiation in conventional multi-bunch mode (100–500 MHz) or laser-based sources with high pulse rate (∼80 MHz) are prohibitive for time-of-flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100 ps range yield only 20–100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron-optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron-optical `pulse-picking' with any desired repetition period. Aberration-free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAX II) and 1.25 MHz (at BESSY II). The approach is compared with two alternative solutions: a bandpass pre-filter (here a hemispherical analyzer) or a parasitic four-bunch island-orbit pulse train, coexisting with the multi-bunch pattern on the main orbit. Chopping in the time domain or bandpass pre-selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100–500 MHz synchrotrons, highly repetitive lasers or cavity-enhanced high-harmonic sources. The high photon flux of a UV-laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region-of-interest (ROI) down to <800 nm. In this novel approach to `sub-µm-ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot.

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Section: Discussionmentioning

confidence: 99%

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Schönhense¹,

Medjanik²,

Fedchenko³

et al. 2021

J Synchrotron Radiat

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“…The main difference being that here the image plane is being projected onto the detector, while in momentum microscopy the back focal plane is imaged and in many cases, both types of imaging can be realised with the same instrument. [253,254] The first HAXPEEM instrument began operation at beamline P09 at PETRAIII and was relocated to beamline P22 in 2018. [57,255] This microscope is based on a NanoESCA instrument (Scienta Omicron GmbH / FOCUS GmbH) modified to operate at higher electron energies.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Hard x-ray photoelectron spectroscopy: a snapshot of the state-of-the-art in 2020

Kalha

Fernando

Bhatt

et al. 2021

J. Phys.: Condens. Matter

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Hard X-ray photoelectron spectroscopy (HAXPES) is establishing itself as an essential technique for the characterisation of materials. The number of specialised photoelectron spectroscopy techniques making use of hard X-rays is steadily increasing and ever more complex experimental designs enable truly transformative insights into the chemical, electronic, magnetic, and structural nature of materials. This paper begins with a short historic perspective of HAXPES and spans from developments in the early days of photoelectron spectroscopy to provide an understanding of the origin and initial development of the technique to state-of-the-art instrumentation and experimental capabilities. The main motivation for and focus of this paper is to provide a picture of the technique in 2020, including a detailed overview of available experimental systems worldwide and insights into a range of specific measurement modi and approaches. We also aim to provide a glimpse into the future of the technique including possible developments and opportunities.

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“…The 2D electron distribution at the output of the immersion lens imaging column is then fed into an energy filter, which in our case is a double-pass hemispherical deflection analyzer (HDA). A transfer lens system between the two HDAs permits us to choose between high energy resolution or high transmission modes, while preserving the 2D characteristics of the photoelectron distribution [22]. Behind the output of the double-pass HDA a transfer lens system transports the electrons into a set of projection lenses, in order to form a magnified spin-integrated intensity image on a 2D detector in the straight direction [ Figure 3(a)].…”

Section: Experimental Realizationmentioning

confidence: 99%

From Photoemission Microscopy to an “All-in-One” Photoemission Experiment

Tusche

Chen

Pluciński

et al. 2020

e-J. Surf. Sci. Nanotechnol.

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Photoelectron spectroscopy is our main tool to explore the electronic structure of novel material systems, the properties of which are often determined by an intricate interplay of competing interactions. Elucidating the role of this interactions requires studies over an extensive range of energy, momentum, length, and time scales. We show that immersion lens-based momentum microscopy with spin-resolution is able to combine these seemingly divergent requirements in a unifying experimental approach. We will discuss applications to different areas in information research, for example, resistive switching and spintronics. The analysis of resistive switching phenomena in oxides requires high lateral resolution and chemical selectivity, as the processes involve local redox processes and oxygen vacancy migration. In spintronics topological phenomena are currently a hot topic, which lead to complex band structures and spin textures in reciprocal space. Spin-resolved momentum microscopy is uniquely suited to address these aspects.

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Imaging properties of hemispherical electrostatic energy analyzers for high resolution momentum microscopy

Cited by 48 publications

References 22 publications

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Hard x-ray photoelectron spectroscopy: a snapshot of the state-of-the-art in 2020

From Photoemission Microscopy to an “All-in-One” Photoemission Experiment

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