Events

An excited electron propagates in condensed matter with its momentum k at an energy E(k) and experiences elastic and inelastic scattering processes, which lead to electronic relaxation and energy transfer to microscopic excitations of the lattice and spin systems. Experiments employing femtosecond time-resolved photoelectron spectroscopy exploited so far very successfully the surface sensitivity of the method and probed such scattering processes locally at or near the surface in the time doma...

Controlling material properties by illumination with ultrashort optical pulses is a promising new pathway to extend the functionality of complex solids. Prominent examples of this rapidly growing research field include photostabilization of superconductivity and switching to metastable states not accessible in thermal equilibrium . A metastable state of particular interest is the optically or electrically induced hidden phase of 1T-TaS2, as it features an order-of-magnitude change in resisti...

We report a time-resolved ultrafast quasiparticle dynamics investigation of cubic boron arsenide (c-BAs), which is a recently discovered highly thermal conducting material. The excited state ultrafast relaxation channels dictated by the electron-phonon coupling (EPC), phonon-phonon scattering, and radiative electron-hole recombination have been unambiguously identified, along with their typical interaction times . Significantly, the EPC strength is obtained from the dynamics, with a value of...

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Using the dynamical mean field theory we investigate the magnetic field dependence of dc conductivity in the Hubbard model on the square lattice, fully taking into account the orbital effects of the field introduced via the Peierls substitution. In addition to the conventional Shubnikov–de Haas quantum oscillations, associated with the coherent cyclotron motion of quasiparticles and the presence of a well-defined Fermi surface, we find an additional oscillatory component with a higher frequ...

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I will discuss the interplay between many-body localization and spin-symmetry. I will present the time evolution of several observables in the anisotropic t − J model. Like the Hubbard chain, the studied model contains charge and spin degrees of freedom. Yet, it has a smaller Hilbert space and thus allows for numerical studies of larger systems. I will compare the field disorder that breaks the Z2 spin symmetry and a potential disorder that preserves the latter symmetry. In the former case,...

In this presentation, we study single-particle properties of quantum-chaotic quadratic models, which are identified with quadratic models having random matrix theory correlations in single-particle spectra, i.e., exhibiting single-particle quantum chaos. We analyze matrix elements of local and nonlocal operators in two paradigmatic Hamiltonians, i.e., the quadratic Sachdev-Ye-Kitaev model and the three-dimensional Anderson model below the localization transition. We demonstrate that their mat...

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By means of time- and angle-resolved photoemission spectroscopy (tr-ARPES), we investigate the effect of the charge density wave (CDW) phase transition on the equilibrium and out-ofequilibrium electronic properties of the transition metal dichalcogenide VSe2. The electronic band structure of VSe2 has recently been subject of investigation ranging from the bulk to the monolayer regime, in search for the manifestation of the opening of the band gap in its CDW phase . However, at present, only a...

IrTe2, a Van-der-Waals transition metal dichalcogenide, is known to host a complicated phase diagram: two first order phase transitions into charge ordered stripe phases of different periodicity are observed in bulk undoped samples : superconductivity emerges in bulk doped samples resulting in the familiar superconducting dome behavior : superconductor – normal metal switching was demonstrated in un-doped quenched nanoflakes : and superconductivity has been shown to emerge in thin flakes re...