Publications (44)
Moiré-resonant surface state in ultrathin RuO
Philipp KeÃler, Andreas Feuerpfeil, Armando Consiglio +9
RuO has emerged as a prototypical candidate for altermagnetism. In the face of daunting evidence for magnetic order in the bulk, the focus naturally shifted to surfaces and ult…
Moiré pattern formation in epitaxial growth on a covalent substrate: Sb on InSb(111)A
Bing Liu, Tim Wagner, Stefan Enzner +4
Structural moiré superstructures arising from two competing lattices may lead to unexpected electronic behavior, such as superconductivity or Mottness. Most investigated moiré he…
Two-Spinon and Orbital Excitations of the Spin-Peierls System TiOCl
Sebastian Glawion, Jakoba Heidler, Maurits W. Haverkort +8
We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polariza…
Toward Functionalized Ultrathin Oxide Films: the Impact of Surface Apical Oxygen
Judith Gabel, Matthias Pickem, Philipp Scheiderer +12
Thin films of transition metal oxides open up a gateway to nanoscale electronic devices beyond silicon characterized by novel electronic functionalities. While such films are commo…
Gate-controlled analog memcapacitance in LaAlO3/SrTiO3 interface-based devices
Soumen Pradhan, Victor Lopez-Richard, Igor Ricardo Filgueira e Silva +8
Current memcapacitor implementations typically demand complex fabrication processes or depend on organic materials exhibiting poor environmental stability and reproducibility. Here…
Graphene intercalation of the large gap quantum spin Hall insulator bismuthene
Lukas Gehrig, Cedric Schmitt, Jonas Erhardt +5
The quantum spin Hall insulator bismuthene, a two-third monolayer of bismuth on SiC(0001), is distinguished by helical metallic edge states that are protected by a groundbreaking 8…
Effects of finite-range interactions on the one-electron spectral properties of TTF-TCNQ
Jose M. P. Carmelo, Tilen Cadez, David K. Campbell +2
The electronic dispersions of the quasi-one-dimensional organic conductor TTF-TCNQ are studied by angle-resolved photoelectron spectroscopy (ARPES) with higher angular resolution a…
Temperature dependent ARPES of the metallic-like bands in Si(553)-Au
Lenart Dudy, Julian Aulbach, Jörg Schäfer +3
We conducted a thorough investigation into the temperature dependence of the metallic-like bands of Si(553)-Au using angular-resolved photoemission spectroscopy (ARPES). Our study…
Phenomenological Modeling of Photoemission Spectra in Strongly Correlated Electron Systems
Krzysztof Byczuk, Ralf Bulla, Ralph Claessen +1
A phenomenological approach is presented that allows one to model, and thereby interpret, photoemission spectra of strongly correlated electron systems. A simple analytical formula…
Non-trivial topological valence bands of common diamond and zinc-blende semiconductors
Tomáš Rauch, Victor A. Rogalev, Maximilian Bauernfeind +11
The diamond and zinc-blende semiconductors are well-known and have been widely studied for decades. Yet, their electronic structure still surprises with unexpected topological prop…
Triangular Spin-Orbit-Coupled Lattice with Strong Coulomb Correlations: Sn Atoms on a SiC(0001) Substrate
Stefan Glass, Gang Li, Florian Adler +6
Two-dimensional (2D) atom lattices provide model setups for Coulomb correlations inducing competing ground states, partly with topological character. Hexagonal SiC(0001) is an intr…
2024 roadmap on 2D topological insulators
Bent Weber, Michael S Fuhrer, Xian-Lei Sheng +22
2D topological insulators promise novel approaches towards electronic, spintronic, and quantum device applications. This is owing to unique features of their electronic band struct…
Design and realization of topological Dirac fermions on a triangular lattice
Maximilian Bauernfeind, Jonas Erhardt, Philipp Eck +8
Large-gap quantum spin Hall insulators are promising materials for room-temperature applications based on Dirac fermions. Key to engineer the topologically non-trivial band orderin…
Hybrid Photoelectron Momentum Microscope at the Soft X-ray Beamline I09 of the Diamond Light Source
Matthias Schmitt, Deepnarayan Biswas, Olena Tkach +7
Soft X-ray momentum microscopy of crystalline solids is a highly efficient approach to map the photoelectron distribution in four-dimensional (E,k) parameter space over the entire…
Magnetic-Order Induced Spectral-Weight Redistribution in a Triangular Surface System
Gang Li, Philipp Höpfner, Jörg Schäfer +6
The Sn-induced surface reconstruction on Si(111) has been investigated by material-specific many-body calculations and by angle-resolved photoelectron spectr…
Inducing ferromagnetism by structural engineering in a strongly spin-orbit coupled oxide
Ji Soo Lim, Carmine Autieri, Merit Spring +17
Magnetic materials with strong spin-orbit coupling (SOC) are essential for the advancement of spin-orbitronic devices, as they enable efficient spin-charge conversion, complex magn…
Stabilizing an atomically thin quantum spin Hall insulator at ambient conditions: Graphene-intercalation of indenene
Cedric Schmitt, Jonas Erhardt, Philipp Eck +11
Atomic monolayers on semiconductor surfaces represent a new class of functional quantum materials at the ultimate two-dimensional limit, ranging from superconductors [1, 2] to Mott…
Backscattering in Topological Edge States Despite Time-Reversal Symmetry
Jonas Erhardt, Mattia Iannetti, Fernando Dominguez +7
Spin-momentum-locked edge states of quantum spin Hall insulators (QSHIs) provide a compelling platform for spintronic applications, owing to their intrinsic protection against back…
Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator
Philipp Scheiderer, Matthias Schmitt, Judith Gabel +7
The Mott transistor is a paradigm for a new class of electronic devices---often referred to by the term Mottronics---, which are based on charge correlations between the electrons.…
High-temperature quantum spin Hall states in buckled III-V-monolayer/SiO$_{2}
Yunyouyou Xia, Suhua Jin, Werner Hanke +2
After establishing the fundamental understanding and the high throughput topological characterization of nearly all inorganic three-dimensional materials, the general interest and…
Spin Chains and Electron Transfer at Stepped Silicon Surfaces
Julian Aulbach, Steven C. Erwin, Ralph Claessen +1
High-index surfaces of silicon with adsorbed gold can reconstruct to form highly ordered linear step arrays. These steps take the form of a narrow strip of graphitic silicon. In so…
Two-dimensional crossover and strong coupling of plasmon excitations in arrays of one-dimensional atomic wires
Timo Lichtenstein, Julian Aulbach, Jörg Schäfer +3
The collective electronic excitations of arrays of Au chains on regularly stepped Si(553) and Si(775) surfaces were studied using electron loss spectroscopy with simultaneous high…
Resonantly-enhanced Raman response in graphene-capped bismuthene on SiC
Lukas Gehrig, Cedric Schmitt, Erica Fragomeni +15
Two-dimensional quantum spin Hall insulators based on atomic monolayers offer a promising route toward dissipationless electronics, yet their practical use is often limited by envi…
Tailoring the topological surface state in ultrathin -Sn (111) films
Victor A. Rogalev, Felix Reis, Florian Adler +11
We report on the electronic structure of -Sn films in the very low thickness regime grown on InSb(111)A. High-resolution low photon energies angle-resolved photoemission (ARPES…
Large-gap quantum anomalous Hall states induced by functionalizing buckled Bi-III monolayer/AlO
Suhua Jin, Yunyouyou Xia, Wujun Shi +5
Chiral edge modes inherent to the topological quantum anomalous Hall (QAH) effect are a pivotal topic of contemporary condensed matter research aiming at future quantum technology…
A new paradigm for the quantum spin Hall effect at high temperatures
Gang Li, Werner Hanke, Ewelina M. Hankiewicz +5
The quantum spin Hall effect (QSHE) has formed the seed for contemporary research on topological quantum states of matter. Since its discovery in HgTe/CdTe quantum wells and AlGaAs…
Oxide Interface-Based Polymorphic Electronic Devices for Neuromorphic Computing
Soumen Pradhan, Kirill Miller, Fabian Hartmann +9
Aside from recent advances in artificial intelligence (AI) models, specialized AI hardware is crucial to address large volumes of unstructured and dynamic data. Hardware-based AI,…
Correlation-driven charge order in a frustrated two-dimensional atom lattice
Florian Adler, Stephan Rachel, Manuel Laubach +4
We thoroughly examine the ground state of the triangular lattice of Pb on Si(111) using scanning tunneling microscopy. We detect charge-order, accompanied by a subtle structural re…
Gate-tunable, normally-on to normally-off memristance transition in patterned LaAlO3/SrTiO3 interfaces
Patrick Maier, Fabian Hartmann, Judith Gabel +8
We report gate-tunable memristive switching in patterned LaAlO3/SrTiO3 interfaces at cryogenic temperatures. The application of voltages in the order of a few volts to the back gat…
Real-space Obstruction in Quantum Spin Hall Insulators
Philipp Eck, Carmine Ortix, Armando Consiglio +6
The recently introduced classification of two-dimensional insulators in terms of topological crystalline invariants has been applied so far to "obstructed" atomic insulators charac…
Observation of room temperature excitons in an atomically thin topological insulator
Marcin Syperek, Raul Stühler, Armando Consiglio +10
Optical spectroscopy of ultimately thin materials has significantly enhanced our understanding of collective excitations in low-dimensional semiconductors. This is particularly ref…
Absence of metallicity in K-doped picene: Importance of electronic correlations
Andreas Ruff, Michael Sing, Ralph Claessen +4
Potassium-doped picene (Kpicene) has recently been reported to be a superconductor at with critical temperatures up to 18 K. Here we study the electronic structure of K-d…
Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2
Teresa Tschirner, Philipp KeÃler, Ruben Dario Gonzalez Betancourt +13
Observations of the anomalous Hall effect in RuO and MnTe have demonstrated unconventional time-reversal symmetry breaking in the electronic structure of a recently identified…
Three-Dimensional Spin Rotations at the Fermi Surface of a Strongly Spin-Orbit Coupled Surface System
Philipp Hoepfner, Joerg Schaefer, Andrzej Fleszar +8
The spin texture of the metallic two-dimensional electron system (root3 x root3)-Au/Ge(111) is revealed by fully three-dimensional spin-resolved photoemission, as well as by densit…
Nature of the metallic and in-gap states in Ni-doped SrTiO
Fatima Alarab, Karol Hricovini, Berengar Leikert +6
Epitaxial thin films of SrTiO(100) doped with 6% and 12% Ni are studied with resonant angle-resolved photoelectron spectroscopy (ARPES) at the Ti and Ni L2,3-edges. We find tha…
Hard x-ray angle-resolved photoemission from a buried high-mobility electron system
Michael Zapf, Matthias Schmitt, Judith Gabel +18
Novel two-dimensional electron systems at the interfaces and surfaces of transition-metal oxides recently have attracted much attention as they display tunable, intriguing properti…
Linear colossal magnetoresistance driven by magnetic textures in LaTiO3 thin films on SrTiO3
Teresa Tschirner, Berengar Leikert, Felix Kern +12
Linear magnetoresistance (LMR) is of particular interest for memory, electronics, and sensing applications, especially when it does not saturate over a wide range of magnetic field…
Lifting topological protection in a quantum spin Hall insulator by edge coupling
Raul Stühler, André Kowalewski, Felix Reis +7
The scientific interest in two-dimensional topological insulators (2D TIs) is currently shifting from a more fundamental perspective to the exploration and design of novel function…
Epitaxial RuO and IrO films by pulsed laser deposition on TiO(110)
Philipp KeÃler, Tim Waldsauer, Vedran Jovic +5
We present a systematic growth study of epitaxial RuO(110) and IrO(110) on TiO(110) substrates by pulsed laser deposition. We describe the main challenges encountered i…
Unoccupied electronic structure of TiOCl studied by x-ray absorption near-edge spectroscopy
Sebastian Glawion, Maurits W. Haverkort, Götz Berner +6
We study the unoccupied electronic structure of the spin-1/2 quantum magnet TiOCl by x-ray absorption near-edge spectroscopy (XANES) at the Ti L and O K edges. Data is acquired bot…
Controlling the electronic interface properties of AlO/SrTiO heterostructures
Berengar Leikert, Judith Gabel, Matthias Schmitt +6
Depositing disordered Al on top of SrTiO is a cheap and easy way to create a two-dimensional electron system in the SrTiO surface layers. To facilitate future device applic…
Towards Topological Quasi-Freestanding Stanene via Substrate Engineering
Domenico Di Sante, Philipp Eck, Maximilian Bauernfeind +5
In search for a new generation of spintronics hardware, material candidates for room temperature quantum spin Hall effect (QSHE) have become a contemporary focus of investigation.…
Testing Topological Protection of Edge States in Hexagonal Quantum Spin Hall Candidate Materials
Fernando Dominguez, Benedikt Scharf, Gang Li +5
We analyze the detailed structure of topological edge mode protection occuring in hexagonal quantum spin Hall (QSH) materials. We focus on bismuthene, antimonene, and arsenene on a…
Double Band Inversion in -Sn: Appearance of Topological Surface States and the Role of Orbital Composition
Victor A. Rogalev, Tomáš Rauch, Markus R. Scholz +9
The electronic structure of \graySn(001) thin films strained compressively in-plane was studied both experimentally and theoretically. A new topological surface state (TSS) located…