Electromagnetic dressing of the electron energy spectrum of Au(111) at high momenta

Keunecke, Marius; Reutzel, Marcel; Schmitt, David R.; Osterkorn, Alexander; Mishra, Tridev; Möller, Christina; Bennecke, Wiebke; Jansen, G. S. Matthijs; Steil, Daniel; Manmana, Salvatore R.; Steil, Sabine; Kehrein, Stefan; Mathias, Stefan

doi:10.1103/physrevb.102.161403

Cited by 27 publications

(19 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, we have performed the analogous simulation of the trARPES signal within the dipole gauge, inserting the matrix elements (33). The comparison of the spectra is shown in Fig.…”

Section: Velocity Gauge Vs Dipole Gaugementioning

confidence: 99%

“…While the transient Hall effect [27,28] gives some hints on global properties, measuring the effective band structure upon periodic driving (Floquet bands) -as enabled by pump-probe time-resolved angleresolved photoemission spectroscopy (trARPES) -yields a detailed microscopic picture. However, the interplay of decoherence [29,30], scattering effects [15,31,32] and screening [33] hamper the direct observation of Floquet states.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Theory of subcycle time-resolved photoemission: application to terahertz photodressing in graphene

Schüler,

Sentef

2021

Preprint

View full text Add to dashboard Cite

Motivated by recent experimental progress we revisit the theory of pump-probe time-and angle-resolved photoemission spectroscopy (trARPES), which is one of the most powerful techniques to trace transient pumpdriven modifications of the electronic properties. The pump-induced dynamics can be described in different gauges for the light-matter interaction. Standard minimal coupling leads to the velocity gauge, defined by linear coupling to the vector potential. In the context of tight-binding (TB) models, the Peierls substitution is the commonly employed scheme for single-band models. Multi-orbital extensions -including the coupling of the dipole moments to the electric field -have been introduced and tested recently. In this work, we derive the theory of time-resolved photoemission within both gauges from the perspective of nonequilibrium Green's functions. This approach naturally incorporates the photoelectron continuum, which allows for a direct calculation of the observable photocurrent. Following this route we introduce gauge-invariant expressions for the time-resolved photoemission signal. The theory is applied to graphene pumped with short terahertz pulses, which we treat within a first-principles TB model. We investigate the gauge invariance and discuss typical effects observed in subcycle time-resolved photoemission. Our formalism is an ideal starting point for realistic trARPES simulations including scattering effects.

show abstract

“…Therefore, we have performed the analogous simulation of the trARPES signal within the dipole gauge, inserting the matrix elements (33). The comparison of the spectra is shown in Fig.…”

Section: Velocity Gauge Vs Dipole Gaugementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theory of subcycle time-resolved photoemission: application to terahertz photodressing in graphene

Schüler,

Sentef

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…For other experimental details, see the Supplemental Material (SM) [24] (see also Refs. [25][26][27][28][29][30][31][32][33][34][35] therein).…”

mentioning

confidence: 99%

Ultrafast electronic linewidth broadening in the C 1s core level of graphene

Curcio¹,

Pakdel²,

Volckaert³

et al. 2021

Phys. Rev. B

View full text Add to dashboard Cite

We show that the presence of a transiently excited hot electron gas in graphene leads to a substantial broadening of the C 1s line probed by time-resolved x-ray photoemission spectroscopy. The broadening is found to be caused by an exchange of energy and momentum between the photoemitted core electron and the hot electron gas, rather than by vibrational excitations. This interpretation is supported by a quantitative line-shape analysis that accounts for the presence of the excited electrons. Fitting the spectra to this model directly yields the electronic temperature of the system, in good agreement with electronic temperature values obtained from valence band data. Furthermore, we show how the momentum change of the outgoing core electrons leads to a detectable but very small change in the time-resolved photoelectron diffraction pattern and to a nearly complete elimination of the core level binding energy variation associated with the presence of a narrow σ band in the C 1s state.

show abstract

“…In order to investigate these micron-scale samples, we make use of our customized time-resolved photoemission system that combines a time-of-flight momentum microscope [37] with a high-repetition-rate high-harmonic generation beamline (Fig. 1a and methods) [38,39]. We induce the ultrafast exciton dynamics by resonantly exciting the A W -exciton in WSe 2 (Fig.…”

mentioning

confidence: 99%

“…a The optical excitation (p-polarized, 1.7 eV-photons) is carried out resonantly with the A W -exciton at the K W -valleys of the WSe 2 Brillouin zone (orange hexagon). Additional spectral weight in the middle of the Brillouin zone arises due the well-known laser-assisted photoelectric effect[39,42]. b Spectral weight is transferred within the WSe 2 layer from the bright A W to the dark Σ W -excitons (small grey hexagon).…”

mentioning

confidence: 99%

Formation of moiré interlayer excitons in space and time

Schmitt,

Bange,

Bennecke

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Moiré superlattices in atomically thin van-der-Waals heterostructures hold great promise for an extended control of electronic and valleytronic lifetimes [1][2][3][4][5][6][7][8], the confinement of excitons in artificial moiré lattices [9][10][11][12][13], and the formation of novel exotic quantum phases [14][15][16][17][18][19]. Such moiré-induced emergent phenomena are particularly strong for interlayer excitons, where the hole and the electron are localized in different layers of the heterostructure [20][21][22]. In order to exploit the full potential of correlated moiré and exciton physics, a thorough understanding of the ultrafast interlayer exciton formation process and the real-space wavefunction confinement in the moiré potential is indispensable. However, direct experimental access to these parameters is limited since most excitonic quasiparticles are optically dark. Here we show that femtosecond photoemission momentum microscopy provides quantitative access to these key properties of the moiré interlayer excitons. We find that interlayer excitons are dominantly formed on the sub-50 fs timescale via interlayer tunneling at the K valleys of the Brillouin zones. In addition, we directly measure energy-momentum fingerprints of the moiré interlayer excitons by mapping their spectral signatures within the mini Brillouin zone that is built up by the twisted heterostructure. From these momentum-fingerprints, we gain quantitative access to the modulation of the exciton wavefunction within the moiré potential in real-space. Our work provides the first direct access to the interlayer moiré exciton formation dynamics in space and time and reveals new opportunities to study correlated moiré and exciton physics for the future realization of exotic quantum phases of matter.

show abstract

Electromagnetic dressing of the electron energy spectrum of Au(111) at high momenta

Cited by 27 publications

References 27 publications

Theory of subcycle time-resolved photoemission: application to terahertz photodressing in graphene

Theory of subcycle time-resolved photoemission: application to terahertz photodressing in graphene

Ultrafast electronic linewidth broadening in the C 1s core level of graphene

Formation of moiré interlayer excitons in space and time

Contact Info

Product

Resources

About