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Université de Fribourg

Entropy and electronic orders of the three-orbital Hubbard model with antiferromagnetic Hund coupling

Yue, Changming ; Hoshino, Shintaro ; Werner, Philipp

In: Physical Review B, 2020, vol. 102, no. 19, p. 195103

An antiferromagnetic Hund coupling in multiorbital Hubbard systems induces orbital freezing and an associated superconducting instability, as well as unique composite orders in the case of an odd number of orbitals. While the rich phase diagram of the half-filled three-orbital model has recently been explored in detail, the properties of the doped system remain to be clarified. Here, we...

Université de Fribourg

High-harmonic generation in spin-orbit coupled systems

Lysne, Markus ; Murakami, Yuta ; Schüler, Michael ; Werner, Philipp

In: Physical Review B, 2020, vol. 102, no. 8, p. 081121

We study high-harmonic generation in two-dimensional electron systems with Rashba and Dresselhaus spin-orbit coupling and derive harmonic generation selection rules with the help of group theory. Based on the band structures of these minimal models and explicit simulations we reveal how the spin-orbit parameters control the cutoff energy in the high-harmonic spectrum. We also show that the...

Université de Fribourg

Entropy and specific heat of the infinite-dimensional three-orbital Hubbard model

Yue, Changming ; Werner, Philipp

In: Physical Review B, 2020, vol. 102, no. 8, p. 085102

The Hund's coupling in multiorbital Hubbard systems induces spin freezing and associated Hund metal behavior. Using dynamical mean-field theory, we explore the effect of local moment formation, spin, and charge excitations on the entropy and specific heat of the three-orbital model. For fillings 2≲n<3 and low temperature, we demonstrate a substantial enhancement of the entropy in the...

Université de Fribourg

Resonance raman optical activity shows unusual structural sensitivity for systems in resonance with multiple excited states: vitamin B12 case

Machalska, Ewa ; Zajac, Grzegorz ; Gruca, Anna ; Zobi, Fabio ; Baranska, Malgorzata ; Kaczor, Agnieszka

In: The Journal of Physical Chemistry Letters, 2020, vol. 11, no. 13, p. 5037–5043

In this work, cobalamins with different upper axial substituents and a cobalamin derivative with a ring modification were studied using chiroptical spectroscopies, in particular resonance Raman optical activity (RROA), to shed light on the influence of structural modifications on RROA spectra in these strongly chiral systems in resonance with multiple excited states at 532 nm excitation. We...

Université de Fribourg

Adsorption-induced kondo effect in metal-free phthalocyanine on Ag(111)

Granet, J. ; Sicot, M. ; Gerber, I. C. ; Kremer, Geoffroy ; Pierron, T. ; Kierren, B. ; Moreau, L. ; Fagot-Revurat, Y. ; Lamare, S. ; Chérioux, F. ; Malterre, D.

In: The Journal of Physical Chemistry C, 2020, vol. 124, no. 19, p. 10441–10452

We report on the formation of a two-dimensional supramolecular Kondo lattice made of organic molecules comprising only C, N, and H atoms, namely metal-free phthalocyanines 2HPc (C32H18N8), adsorbed on a Ag(111) surface. Low-temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS), ultraviolet photoemission spectroscopy (UPS), and density functional theory (DFT) are used to...

Université de Fribourg

Coupling of electronic and nuclear motion in a negative ion resonance: Experimental and theoretical study of benzene

Allan, Michael ; Čurík, Roman ; Čársky, Petr

In: The Journal of Chemical Physics, 2019, vol. 151, no. 6, p. 064119

We present calculated and measured elastic and vibrational excitation cross sections in benzene with the objective to assess the reliability of the theoretical method and to shed more light on how the electronic motion of the incoming electron is coupled with the nuclear motion of the vibrations. The calculation employed the discrete momentum representation method which involves solving the...

Consortium of Swiss Academic Libraries

Explaining the heat capacity of wood constituents by molecular vibrations

Thybring, Emil

In: Journal of Materials Science, 2014, vol. 49, no. 3, p. 1317-1327