Status and strategy at ISA, centre for storage ring facilities, Aarhus University, Denmark

Bianchi, Marco; Hofmann, Philip; Hoffmann, Søren Vrønning; Jones, Nykola C.; Li, Zheshen; Miwa, Jill A.; Møller, S.P.; Nielsen, Jørgen S.; Thomsen, Heine; Ulstrup, Søren; Worm, T.

doi:10.1140/epjp/s13360-023-03748-1

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…In situ Rb deposition on the surfaces of bulk crystals of the basic building blocks MnBi 2 Te 4 and Bi 2 Te 3 as well as the two possible surface terminations of MnBi 4 Te 7 is tracked by ARPES with microscale spatial resolution at the new SGM4 beamline for micro‐ and nanoARPES at the ASTRID2 light source, Aarhus University. [ 43 ] Photons with tunable energy over a range of 14–150 eV are obtained from an undulator insertion device and selected using a spherical grating monochromator (SGM‐type). An intermediate beam focus with a diameter on the order of 60 µm is achieved using two separate plane ellipse mirrors placed after the monochromator.…”

Section: Resultsmentioning

confidence: 99%

“…Photoemission Measurements:: The microARPES measurements were performed at the SGM4 beamline of the ASTRID2 synchrotron radiation source at Aarhus University, Denmark. [43] The MnBi 2 Te 4 , MnBi 4 Te 7 , and Bi 2 Te 3 crystals were cleaved in situ and measured at a temperature of 120 K in a base pressure better than 1 • 10 −10 mbar. The Mn(Sb d Bi (1 − d) ) 2 Te 4 samples were cleaved in situ at room temperature and a base pressure better than 5 • 10 −8 mbar.…”

Section: Methodsmentioning

confidence: 99%

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Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

Volckaert,

Majchrzak,

Biswas

et al. 2023

Advanced Materials

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Modification of the electronic structure of quantum matter by ad atom deposition allows for directed fundamental design of electronic and magnetic properties. This concept is utilized in the present study in order to tune the surface electronic structure of magnetic topological insulators based on MnBi2Te4. The topological bands of these systems are typically strongly electron‐doped and hybridized with a manifold of surface states that place the salient topological states out of reach of electron transport and practical applications. In this study, micro‐focused angle‐resolved photoemission spectroscopy (microARPES) provides direct access to the termination‐dependent dispersion of MnBi2Te4 and MnBi4Te7 during in situ deposition of rubidium atoms. The resulting band structure changes are found to be highly complex, encompassing coverage‐dependent ambipolar doping effects, removal of surface state hybridization, and the collapse of a surface state band gap. In addition, doping‐dependent band bending is found to give rise to tunable quantum well states. This wide range of observed electronic structure modifications can provide new ways to exploit the topological states and the rich surface electronic structures of manganese bismuth tellurides.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

Volckaert,

Majchrzak,

Biswas

et al. 2023

Advanced Materials

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“…Here, we present a detailed microARPES study of a tBLG device with a twist angle around the magic angle performed at the SGM4 beamline of the ASTRID2 light source at Aarhus University, Denmark [35,36]. We characterize the spatially-dependent electronic structure of the tBLG device and examine spectral intensity variations stemming from photon energy-dependent photoelectron interference effects.…”

Section: Introductionmentioning

confidence: 99%

Revealing flat bands and hybridization gaps in a twisted bilayer graphene device with microARPES

Jiang,

Hsieh,

Jones

et al. 2023

2D Mater.

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Controlling the electronic structure of two-dimensional materials using the combination of twist angle and electrostatic doping is an effective means to induce emergent phenomena. In bilayer graphene with an interlayer twist angle near the magic angle, the electronic dispersion is strongly modified by a manifold of hybridizing moiré Dirac cones leading to flat band segments with strong electronic correlations. Numerous technical challenges arising from spatial inhomogeneity of interlayer interactions, twist angle and device functionality have so far limited momentum-resolved electronic structure measurements of these systems to static conditions. Here, we present a detailed characterization of the electronic structure exhibiting miniband dispersions for twisted bilayer graphene, near the magic angle, integrated in a functional device architecture using micro-focused angle-resolved photoemission spectroscopy. The optimum conditions for visualizing the miniband dispersion are determined by exploiting the spatial resolution and photon energy tunability of the light source and applied to extract a hybridization gap size of (0.14 ± 0.03) eV and flat band segments extending across a moiré mini Brillouin zone. In situ electrostatic gating of the sample enables significant electron-doping, causing the conduction band states to shift below the Fermi energy. Our work emphasizes key challenges in probing the electronic structure of magic angle bilayer graphene devices and outlines conditions for exploring the doping-dependent evolution of the dispersion that underpins the ability to control many-body interactions in the material.

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Characterization of semiconductors by synchrotron-based techniques

Benter,

Mikkelsen

2025

Comprehensive Semiconductor Science and Technology

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Status and strategy at ISA, centre for storage ring facilities, Aarhus University, Denmark

Cited by 5 publications

References 27 publications

Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

Revealing flat bands and hybridization gaps in a twisted bilayer graphene device with microARPES

Characterization of semiconductors by synchrotron-based techniques

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