Malte Selig
Technische Universität Berlin
H-index: 25
Europe-Germany
About Malte Selig
Malte Selig, With an exceptional h-index of 25 and a recent h-index of 25 (since 2020), a distinguished researcher at Technische Universität Berlin,
His recent articles reflect a diverse array of research interests and contributions to the field:
Dipolar coupling at interfaces of ultrathin semiconductors, semimetals, plasmonic nanoparticles, and molecules
Fermionic versus bosonic thermalization in phonon-driven exciton dynamics: An analytic dimensionality study
Data-Driven Acceleration of Multi-Physics Simulations
Spatial exciton localization at interfaces of metal nanoparticles and atomically thin semiconductors
Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor
Time-resolved single-particle x-ray scattering reveals electron-density gradients as coherent plasmonic-nanoparticle-oscillation source
Strong Coupling of Two-Dimensional Excitons and Plasmonic Photonic Crystals: Microscopic Theory Reveals Triplet Spectra
Theory of radial oscillations in metal nanoparticles driven by optically induced electron density gradients
Malte Selig Information
University | Technische Universität Berlin |
---|---|
Position | ___ |
Citations(all) | 2893 |
Citations(since 2020) | 2627 |
Cited By | 1238 |
hIndex(all) | 25 |
hIndex(since 2020) | 25 |
i10Index(all) | 36 |
i10Index(since 2020) | 36 |
University Profile Page | Technische Universität Berlin |
Top articles of Malte Selig
Dipolar coupling at interfaces of ultrathin semiconductors, semimetals, plasmonic nanoparticles, and molecules
Authors
Lara Greten,Robert Salzwedel,Manuel Katzer,Henry Mittenzwey,Dominik Christiansen,Andreas Knorr,Malte Selig
Journal
physica status solidi (a)
Published Date
2024/1
Recent progress in growth techniques has enabled the fabrication of stacks of transition metal dichalcogenide monolayers combined with different nanostructures ranging from other 2D layers over dye molecules to even plasmonic nanoparticles. Such structures promise to combine the optoelectric properties of the constituents allowing to design structures with desired properties. For all of these examples, a detailed knowledge of the coupling among different constituents is crucial. In this article, a unified description is presented based on Maxwell Bloch equations to describe dipolar interactions among different types of heterostructures. Exemplary, Förster‐type energy transfer from dye molecules to MoS2 monolayers, strong coupling at MoSe2–metal nanoparticle interfaces, Meitner–Auger‐like interlayer coupling in WSe2–graphene stacks, and relaxation processes of hot interlayer excitons in MoSe2–WSe2 …
Fermionic versus bosonic thermalization in phonon-driven exciton dynamics: An analytic dimensionality study
Authors
Manuel Katzer,Malte Selig,Andreas Knorr
Journal
Physical Review B
Published Date
2024/4/2
Excitons are compound particles formed from an electron and a hole in semiconductors. The impact of this substructure on the phonon-exciton interaction is described by a closed system of microscopic scattering equations. To calculate the actual excitonic thermalization properties beyond the pure bosonic picture, this equation is derived directly from an electron-hole picture within the Heisenberg equation of motion framework. In addition to the well-known bosonic character of the compound particles, we identified processes of a repulsive, fermionic type, as well as attractive carrier exchange contributing to the scattering process. In this analytical study we give general statements about the thermalization of excitons in two-and three-dimensional semiconductors. We give insights on the strong dependence of the thermalization characteristics of the exciton Bohr radius and the thermalization wavelength. Above all, we …
Data-Driven Acceleration of Multi-Physics Simulations
Authors
Stefan Meinecke,Malte Selig,Felix Köster,Andreas Knorr,Kathy Lüdge
Journal
arXiv preprint arXiv:2402.16433
Published Date
2024/2/26
Multi-physics simulations play a crucial role in understanding complex systems. However, their computational demands are often prohibitive due to high dimensionality and complex interactions, such that actual calculations often rely on approximations. To address this, we introduce a data-driven approach to approximate interactions among degrees of freedom of no direct interest and thus significantly reduce computational costs. Focusing on a semiconductor laser as a case study, we demonstrate the superiority of this method over traditional analytical approximations in both accuracy and efficiency. Our approach streamlines simulations, offering promise for complex multi-physics systems, especially for scenarios requiring a large number of individual simulations.
Spatial exciton localization at interfaces of metal nanoparticles and atomically thin semiconductors
Authors
Robert Salzwedel,Lara Greten,Stefan Schmidt,Stephen Hughes,Andreas Knorr,Malte Selig
Journal
Physical Review B
Published Date
2024/1/30
We present a self-consistent Maxwell-Bloch theory to analytically study the interaction between a nanostructure consisting of a metal nanoparticle and a monolayer of transition-metal dichalcogenide. For the combined system, we identify an effective eigenvalue equation that governs the center-of-mass motion of the dressed excitons in a plasmon-induced potential. Examination of the dynamical equation of the exciton-plasmon hybrid reveals the existence of bound states with negative eigenenergies, which we interpret as excitons localized in the plasmon-induced potential. The appearance of these bound states in the potential indicates strong coupling between excitons and plasmons. We quantify this coupling regime by computing the scattered light in the near-field explicitly and identify signatures of strong exciton-plasmon coupling with an avoided crossing behavior and an effective Rabi splitting of tens of meV.
Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor
Authors
M Wurdack,T Yun,M Katzer,AG Truscott,A Knorr,M Selig,EA Ostrovskaya,E Estrecho
Journal
Nature Communications
Published Date
2023/2/23
Dispersion engineering is a powerful and versatile tool that can vary the speed of light signals and induce negative-mass effects in the dynamics of particles and quasiparticles. Here, we show that dissipative coupling between bound electron-hole pairs (excitons) and photons in an optical microcavity can lead to the formation of exciton polaritons with an inverted dispersion of the lower polariton branch and hence, a negative mass. We perform direct measurements of the anomalous dispersion in atomically thin (monolayer) WS2 crystals embedded in planar microcavities and demonstrate that the propagation direction of the negative-mass polaritons is opposite to their momentum. Our study introduces the concept of non-Hermitian dispersion engineering for exciton polaritons and opens a pathway for realising new phases of quantum matter in a solid state.
Time-resolved single-particle x-ray scattering reveals electron-density gradients as coherent plasmonic-nanoparticle-oscillation source
Authors
Dominik Hoeing,Robert Salzwedel,Lena Worbs,Yulong Zhuang,Amit K Samanta,Jannik Lübke,Armando D Estillore,Karol Dlugolecki,Christopher Passow,Benjamin Erk,Nagitha Ekanayake,Daniel Ramm,Jonathan Correa,Christina C Papadopoulou,Atia Tul Noor,Florian Schulz,Malte Selig,Andreas Knorr,Kartik Ayyer,Jochen Küpper,Holger Lange
Journal
Nano Letters
Published Date
2023/6/23
Dynamics of optically excited plasmonic nanoparticles are presently understood as a series of scattering events involving the initiation of nanoparticle breathing oscillations. According to established models, these are caused by statistical heat transfer from thermalized electrons to the lattice. An additional contribution by hot-electron pressure accounts for phase mismatches between theory and experimental observations. However, direct experimental studies resolving the breathing-oscillation excitation are still missing. We used optical transient-absorption spectroscopy and time-resolved single-particle X-ray diffractive imaging to access the electron system and lattice. The time-resolved single-particle imaging data provided structural information directly on the onset of the breathing oscillation and confirmed the need for an additional excitation mechanism for thermal expansion. We developed a new model that …
Strong Coupling of Two-Dimensional Excitons and Plasmonic Photonic Crystals: Microscopic Theory Reveals Triplet Spectra
Authors
Lara Greten,Robert Salzwedel,Tobias Göde,David Greten,Stephanie Reich,Stephen Hughes,Malte Selig,Andreas Knorr
Journal
arXiv preprint arXiv:2309.09673
Published Date
2023/9/18
Monolayers of transition metal dichalcogenides (TMDC) are direct-gap semiconductors with strong light-matter interactions featuring tightly bound excitons, while plasmonic crystals (PCs), consisting of metal nanoparticles that act as meta-atoms, exhibit collective plasmon modes and allow one to tailor electric fields on the nanoscale. Recent experiments show that TMDC-PC hybrids can reach the strong-coupling limit between excitons and plasmons forming new quasiparticles, so-called plexcitons. To describe this coupling theoretically, we develop a self-consistent Maxwell-Bloch theory for TMDC-PC hybrid structures, which allows us to compute the scattered light in the near- and far-field explicitly and provide guidance for experimental studies. Our calculations reveal a spectral splitting signature of strong coupling of more than meV in gold-MoSe structures with nm nanoparticles, manifesting in a hybridization of exciton and plasmon into two effective plexcitonic bands. In addition to the hybridized states, we find a remaining excitonic mode with significantly smaller coupling to the plasmonic near-field, emitting directly into the far-field. Thus, hybrid spectra in the strong coupling regime can contain three emission peaks.
Theory of radial oscillations in metal nanoparticles driven by optically induced electron density gradients
Authors
Robert Salzwedel,Andreas Knorr,Dominik Hoeing,Holger Lange,Malte Selig
Journal
The Journal of Chemical Physics
Published Date
2023/2/14
We provide a microscopic approach to describe the onset of radial oscillation of a silver nanoparticle. Using the Heisenberg equation of motion framework, we find that the coupled ultrafast dynamics of coherently excited electron occupation and the coherent phonon amplitude initiate periodic size oscillations of the nanoparticle. Compared to the established interpretation of experiments, our results show a more direct coupling mechanism between the field intensity and coherent phonons. This interaction triggers a size oscillation via an optically induced electron density gradient occurring directly with the optical excitation. This source is more efficient than the incoherent heating process currently discussed in the literature and well-describes the early onset of the oscillations in recent experiments.
Data-driven forecasting of nonequilibrium solid-state dynamics
Authors
Stefan Meinecke,Felix Köster,Dominik Christiansen,Kathy Lüdge,Andreas Knorr,Malte Selig
Journal
Physical Review B
Published Date
2023/5/11
We present a data-driven approach to efficiently approximate nonlinear transient dynamics in solid-state systems. Our proposed machine-learning model combines a dimensionality reduction stage with a nonlinear vector autoregression scheme. We report an outstanding time-series forecasting performance combined with an easy-to-deploy model and an inexpensive training routine. Our results are of great relevance as they have the potential to massively accelerate multiphysics simulation software and thereby guide the future development of solid-state-based technologies.
PHYSIKALISCHES KOLLOQUIUM Wintersemester 2023/24
Authors
Ralph Ernstorfer,Samuel Beaulieu,Sebastian Hammer,D Zahn,YW Windsor,Julian Maklar,R Patrick Xian,Malte Selig,Dominik Christiansen,Andreas Knorr,Martin Wolf,Jens Pflaum,Laurenz Rettig
Published Date
2023/12/4
The dynamics of quasi-particles in non-equilibrium states of matter reveal the underlying microscopic coupling between electronic, spin and vibrational degrees of freedom. We aim for a quantum-state-resolved picture of coupling on the level of quasi-particle self-energies, which goes beyond established ensemble-average descriptions, and which requires ultrafast momentum-resolving techniques. Electronic and excitonic excitations are measured with time-and angle-resolved photoemission spectroscopy (trARPES). While (tr) ARPES data is traditionally interpreted in a single-particle band-structure picture, we developed approaches to access the key properties of many-body states with multidimensional photoemission spectroscopy. I will exemplify these approaches for excitons in transition metal dichalcogenide semiconductors [1] and van der Waals heterostructures. TrARPES can
Optical classification of excitonic phases in molecular functionalized atomically-thin semiconductors
Authors
Dominik Christiansen,Malte Selig,Mariana Rossi,Andreas Knorr
Journal
Physical Review B
Published Date
2023/1/9
The excitonic insulator is an elusive electronic phase exhibiting a correlated excitonic ground state. Materials with such a phase are expected to have intriguing properties such as excitonic high-temperature superconductivity. However, compelling evidence on the experimental realization is still missing. Here, we theoretically propose hybrids of two-dimensional semiconductors functionalized by organic molecules as prototypes of excitonic insulators, with the exemplary candidate WS 2-F6TCNNQ. This material system exhibits an excitonic insulating phase at room temperature with a ground state formed by a condensate of interlayer excitons. To address an experimentally relevant situation, we calculate the corresponding phase diagram for the important parameters: temperature, gap energy, and dielectric environment. Further, to guide future experimental detection, we show how to optically characterize the …
Theory of x-ray absorption spectroscopy: A microscopic Bloch equation approach for two-dimensional solid states
Authors
Dominik Christiansen,Malte Selig,Jens Biegert,Andreas Knorr
Journal
Physical Review Research
Published Date
2023/4/3
We develop a self-consistent Maxwell-Bloch formalism for the interaction of x-rays with two-dimensional crystalline materials by incorporating the Bloch theorem and Coulomb many-body interaction. This formalism is illustrated for graphene, by calculating the polarization-dependent XANES, formulating expressions for the radiative and Meinter-Auger recombination of core holes, and the discussion of microscopic insights into the spectral oscillations of EXAFS beyond point scattering theory. In particular, the correct inclusion of lattice periodicity in our evaluation allows us to assign so far uninterpreted spectral features in the Fourier transformed EXAFS spectrum.
Time-domain observation of interlayer exciton formation and thermalization in a MoSe2/WSe2 heterostructure
Authors
Veronica R Policht,Henry Mittenzwey,Oleg Dogadov,Manuel Katzer,Andrea Villa,Qiuyang Li,Benjamin Kaiser,Aaron M Ross,Francesco Scotognella,Xiaoyang Zhu,Andreas Knorr,Malte Selig,Giulio Cerullo,Stefano Dal Conte
Journal
Nature Communications
Published Date
2023/11/10
Vertical heterostructures of transition metal dichalcogenides (TMDs) host interlayer excitons with electrons and holes residing in different layers. With respect to their intralayer counterparts, interlayer excitons feature longer lifetimes and diffusion lengths, paving the way for room temperature excitonic optoelectronic devices. The interlayer exciton formation process and its underlying physical mechanisms are largely unexplored. Here we use ultrafast transient absorption spectroscopy with a broadband white-light probe to simultaneously resolve interlayer charge transfer and interlayer exciton formation dynamics in a MoSe2/WSe2 heterostructure. We observe an interlayer exciton formation timescale nearly an order of magnitude (~1 ps) longer than the interlayer charge transfer time (~100 fs). Microscopic calculations attribute this relative delay to an interplay of a phonon-assisted interlayer exciton cascade and …
Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors
Authors
Manuel Katzer,Sviatoslav Kovalchuk,Kyrylo Greben,Kirill I Bolotin,Malte Selig,Andreas Knorr
Journal
Physical Review B
Published Date
2023/1/6
Interfaces of dye molecules and two-dimensional transition metal dichalcogenides (TMDCs) combine strong molecular dipole excitations with high carrier mobilities in semiconductors. Förster type energy transfer is one key mechanism for the coupling between both constituents. We report microscopic calculations of a spectrally resolved Förster induced transition rate from dye molecules to a TMDC layer. Our approach is based on microscopic Bloch equations which are solved self-consistently together with Maxwell's equations. This approach allows to incorporate the dielectric environment of a TMDC semiconductor, sandwiched between donor molecules and a substrate. Our analysis reveals transfer rates in the meV range for typical dye molecules in closely stacked structures, with a nontrivial dependence of the Förster rate on the molecular transition energy resulting from unique signatures of dark, momentum …
Interlayer excitons in semiconductor bilayers under a strong electric field
Authors
S Kovalchuk,K Greben,A Kumar,S Pessel,K Watanabe,T Taniguchi,D Christiansen,M Selig,A Knorr,KI Bolotin
Journal
arXiv preprint arXiv:2303.09931
Published Date
2023/3/17
Excitons in bilayer transition metal dichalcogenides (2L-TMDs) are Coulomb-bound electron/hole pairs that can be viewed as broadly tunable analogs of atomic or molecular systems. Here, we study the properties of 2L-TMD excitons under strong electric field. To overcome the field limit, reached in previous experiments, we developed a new organic/inorganic molecular gating technique. Our approach allows reaching the field > 0.27 V nm-1, about twice higher than previously available. Under this field inter and intra-layer excitonic are brought into an energetic resonance, allowing us to discover new emergent properties of the resulting hybridized states. First, as the result of hybridization, intralayer excitons acquire an interlayer character. Second, the same hybridization allows us to detect new excitonic species. Third, we observe an ultra-strong Stark splitting of > 380 meV with exciton energies tunable over a large range of the optical spectrum, with potential implications for optoelectronics. Our work creates new possibilities for using strong electric fields to unlock new physical regimes and control exciton hybridization in 2D heterostructures and other systems.
Observation of ultrafast interfacial Meitner-Auger energy transfer in a Van der Waals heterostructure
Authors
Shuo Dong,Samuel Beaulieu,Malte Selig,Philipp Rosenzweig,Dominik Christiansen,Tommaso Pincelli,Maciej Dendzik,Jonas D Ziegler,Julian Maklar,R Patrick Xian,Alexander Neef,Avaise Mohammed,Armin Schulz,Mona Stadler,Michael Jetter,Peter Michler,Takashi Taniguchi,Kenji Watanabe,Hidenori Takagi,Ulrich Starke,Alexey Chernikov,Martin Wolf,Hiro Nakamura,Andreas Knorr,Laurenz Rettig,Ralph Ernstorfer
Journal
arXiv preprint arXiv:2108.06803
Published Date
2021/8/15
Atomically thin layered van der Waals heterostructures feature exotic and emergent optoelectronic properties. With growing interest in these novel quantum materials, the microscopic understanding of fundamental interfacial coupling mechanisms is of capital importance. Here, using multidimensional photoemission spectroscopy, we provide a layer- and momentum-resolved view on ultrafast interlayer electron and energy transfer in a monolayer-WSe2/graphene heterostructure. Depending on the nature of the optically prepared state, we find the different dominating transfer mechanisms: while electron injection from graphene to WSe2 is observed after photoexcitation of quasi-free hot carriers in the graphene layer, we establish an interfacial Meitner-Auger energy transfer process following the excitation of excitons in WSe2. By analysing the time-energy-momentum distributions of excited-state carriers with a rate …
New interlayer excitons in 2D bilayers revealed under strong electric field
Authors
Kirill Bolotin,Sviatoslav Kovalchuk,Kyrylo Greben,Abhijeet Kumar,Simon Pessel,Jan Soyka,Qing Cao,Kenji Watanabe,Takashi Taniguchi,Dominik Christiansen,Malte Selig,Andreas Knorr,Eigler Siegfried
Published Date
2023/10/30
Excitons in bilayer transition metal dichalcogenides (2L-TMDs) are Coulomb-bound electron/hole pairs that can be viewed as broadly tunable analogs of atomic or molecular systems. Here, we study the properties of 2L-TMD excitons under a strong electric field. To overcome the field limit reached in previous experiments, we developed a new organic/inorganic molecular gating technique. This approach allows us to achieve an electric field strengh of about 0.35 V nm-1, more than a factor of two higher than achieved previously in purely solid-state gated devices. Under this field, inter-and intralayer excitons are brought into an energetic resonance, allowing us to discover new emergent properties of the resulting states. We detect a previously unseen interlayer exciton that only becomes visible at high electric field through hybridization with intralayer A exciton. Moreover, the system experiences an ultra-strong Stark splitting of> 380 meV with exciton energies tunable over a large range of the optical spectrum, holding potential for optoelectronics. Our work paves the way for using strong electric fields to study new physical regimes and control exciton hybridization in 2D semiconductors.
Publisher Correction: Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor
Authors
M Wurdack,T Yun,M Katzer,AG Truscott,A Knorr,M Selig,EA Ostrovskaya,E Estrecho
Journal
nature communications
Published Date
2023/3/2
In the original version of this Article, an acknowledgment sentence was erroneously inserted in the last paragraph of page 3. The sentence read ‘(The fabrication of the high-reflectivity substrate was performed at the ACT OptoFab node of the Australian National Fabrication Facility—a company established under the National Collaborative Research Infrastructure Strategy to provide nano and microfabrication facilities for Australia’s researchers.)’. This sentence has now been removed.One sentence in the Acknowledgments section, which read ‘We acknowledge the Australian National Fabrication Facility (ANFF) OptoFab at its node in the Australian Capital Territory (ACT) for fabricating the high-quality DBR substrate, and the ANFF ACT node for the technical support in sample fabrication.’, has been replaced with the following:‘We acknowledge the Australian National Fabrication Facility (ANFF) OptoFab, a company …
Extended Spatial Coherence of Interlayer Excitons in Heterobilayers
Authors
Mirco Troue,Johannes Figueiredo,Lukas Sigl,Christos Paspalides,Manuel Katzer,Takashi Taniguchi,Kenji Watanabe,Malte Selig,Andreas Knorr,Ursula Wurstbauer,Alexander W Holleitner
Journal
Physical Review Letters
Published Date
2023/7/19
We report on the spatial coherence of interlayer exciton ensembles as formed in MoSe 2/WSe 2 heterostructures and characterized by point-inversion Michelson-Morley interferometry. Below 10 K, the measured spatial coherence length of the interlayer excitons reaches values equivalent to the lateral expansion of the exciton ensembles. In this regime, the light emission of the excitons turns out to be homogeneously broadened in energy with a high temporal coherence. At higher temperatures, both the spatial coherence length and the temporal coherence time decrease, most likely because of thermal processes. The presented findings point towards a spatially extended, coherent many-body state of interlayer excitons at low temperature.
Impact of optically pumped nonequilibrium steady states on luminescence emission of atomically thin semiconductor excitons
Authors
Manuel Katzer,Malte Selig,Dominik Christiansen,Mariana V Ballottin,Peter CM Christianen,Andreas Knorr
Journal
Physical Review Letters
Published Date
2023/10/2
The interplay of the nonequivalent corners in the Brillouin zone of transition metal dichalcogenides (TMDCs) has been investigated extensively. While experimental and theoretical works contributed to a detailed understanding of the relaxation of selective optical excitations and the related relaxation rates, only limited microscopic descriptions of stationary experiments are available so far. Here we present microscopic calculations for the nonequilibrium steady state properties of excitons during continuous wave pumping exemplary for monolayer MoSe 2. We find sharp features in photoluminescence excitation spectra and degree of polarization which result from phonon assisted excitonic transitions dominating over exciton recombination and intervalley exchange coupling.
Malte Selig FAQs
What is Malte Selig's h-index at Technische Universität Berlin?
The h-index of Malte Selig has been 25 since 2020 and 25 in total.
What are Malte Selig's top articles?
The articles with the titles of
Dipolar coupling at interfaces of ultrathin semiconductors, semimetals, plasmonic nanoparticles, and molecules
Fermionic versus bosonic thermalization in phonon-driven exciton dynamics: An analytic dimensionality study
Data-Driven Acceleration of Multi-Physics Simulations
Spatial exciton localization at interfaces of metal nanoparticles and atomically thin semiconductors
Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor
Time-resolved single-particle x-ray scattering reveals electron-density gradients as coherent plasmonic-nanoparticle-oscillation source
Strong Coupling of Two-Dimensional Excitons and Plasmonic Photonic Crystals: Microscopic Theory Reveals Triplet Spectra
Theory of radial oscillations in metal nanoparticles driven by optically induced electron density gradients
...
are the top articles of Malte Selig at Technische Universität Berlin.
What is Malte Selig's total number of citations?
Malte Selig has 2,893 citations in total.
What are the co-authors of Malte Selig?
The co-authors of Malte Selig are Tony F Heinz, Giulio Cerullo, Ermin Malic, Rudolf Bratschitsch, Tobias Korn, Christian Schüller.