The European Physical Journal B最新文献

Using dynamical mean-field theory (DMFT), we explore the many-particle properties of an extended two-band Hubbard model applicable to 2H-TaSe(_2) superconductor. We reveal the electronic reconstruction of the CDW-Mott state driven by site-diagonal disorder with distinct many-particle excitations. Our results offer new microscopic theory insights into the Mott–Anderson nature of charge carriers and the correlated metallic state which emerges from site-diagonal disorder within the CDW-Mott regime.

Racism remains a persistent societal issue, increasingly amplified by the structure and dynamics of online social networks. In this work, we propose a three-state compartmental model to study the spreading and suppression of racist content, drawing from epidemic-like dynamics and interaction-driven transitions. We analyze the model on fully connected (homogeneous mixing) networks using a set of coupled differential equations, and on Barabási–Albert scale-free and Watts–Strogatz small-world networks through agent-based simulations. The system exhibits three distinct stationary regimes: two racism-free absorbing states and one active phase with persistent racist content. We identify and characterize the phase transitions between these regimes, discuss the role of network topology, and highlight the emergence of absorbing states. Our findings illustrate how statistical physics tools can help uncover the macroscopic consequences of microscopic social interactions in digital environments.

This study systematically investigates the modulation of deep strain-induced indirect-to-direct bandgap transition in boron arsenide (BAs) using first-principles calculations. Uniaxial tensile and compressive strains are applied along [001], [110], and [111] directions to explore the electronic structure evolution. Results show that compressive strains along all three directions cause linear decreases in the bandgap until metallic transition, while tensile strains exhibit anisotropic behaviors. Notably, stretching along [111] direction triggers an indirect-to-direct bandgap transition at a critical strain of 0.12: the conduction band energy at (Gamma ) point decreases faster than that near X point, leading to the bottom of the conduction band shifting from X to (Gamma ) point. The density of states analysis confirms that the Fermi surface electrons are primarily contributed by B and As p-electrons, remaining unchanged during the bandgap transition. This work provides theoretical insights for strain-engineered optoelectronic applications of BAs.

Herein, we report on self-sustaining acoustoelectric direct current oscillations in fluorine-doped single-walled carbon nanotubes stimulated by a strong internal electric field. The study is carried out in the hypersound regime, where carrier transport is confined to the lowest electronic miniband, leading to enhanced nonlinear and non-monotonic acoustoelectric current response. The carrier dynamics predicted by the model are consistent with experimentally observed oscillatory acoustoelectric current in a graphene-based acoustoelectric switch. The oscillatory behavior is shown to originate from spatial charge instabilities and field-induced Bloch-like carrier dynamics, occurring in the absence of an external resonator. The resulting non-uniform space-charge distribution, together with Bloch-reflected carrier motion, is identified as the dominant mechanism responsible for terahertz radiation generation. In addition, the dynamic interplay between acoustic phonons and charge carriers suggests the possibility of suppressing electric domain formation and realizing acoustic Bloch gain. These results demonstrate that fluorine-doped single-walled carbon nanotubes can operate efficiently at elevated temperatures and are promising candidates for high-frequency electronic and optoelectronic applications extending into the submillimeter-wave regime.