We propose an electric circuit array with topologically protected unidirectional voltage modes at its boundary. Instead of external bias fields or Floquet engineering, we employ negative impedance converters with current inversion (INICs) to accomplish a nonreciprocal, time-reversal symmetry-broken electronic network we call a topolectrical Chern circuit (TCC). The TCC features an admittance bulk gap fully tunable via the resistors used in the INICs, along with a chiral voltage boundary mode reminiscent of the Berry flux monopole present in the admittance band structure. The active circuit elements in the TCC can be calibrated to compensate for dissipative loss.
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http://dx.doi.org/10.1103/PhysRevLett.122.247702 | DOI Listing |
Light Sci Appl
January 2025
Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, 19716, USA.
Exceptional points (EPs) have been extensively explored in mechanical, acoustic, plasmonic, and photonic systems. However, little is known about the role of EPs in tailoring the dynamic tunability of optical devices. A specific type of EPs known as chiral EPs has recently attracted much attention for controlling the flow of light and for building sensors with better responsivity.
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December 2024
Institute for Chemical Research, Kyoto University Gokasho, Uji Kyoto 611-0011 Japan
Although fullerene bisadducts are promising electron-transporting materials for tin halide perovskite solar cells, they are generally synthesized as a mixture of isomeric products that require a complicated separation process. Here, we introduce a phenylene-bridged bis(pyrrolidino)fullerene, Bis-PC, which forms only a single isomer due to geometrical restriction. When used in a tin perovskite solar cell with a PEAFASnI (PEA: phenylethylammonium and FA: formamidinium) light absorption layer, the resulting open-circuit voltage ( ) was 0.
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen University, Shenzhen, 518060, China; Marshall Laboratory of Biomedical Engineering, Shenzhen Key Laboratory of Nano-Biosensing Technology, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518060, China. Electronic address:
Highly ordered ultrathin nanosheets (NSs) of Au(I)-Cys were fabricated through aggregation-induced supramolecular self-assembly triggered by an extended agitation in an alkaline environment. The synthesized Au(I)-Cys NSs exhibited intense luminescence and exceptional chirality. Remarkably, additions of biothiols to Au(I)-Cys NSs have significantly enhanced their luminescence emission, and circular dichroism properties coupled with morphological modulations into nanoflowers, nanodendrites, or closely packed aggregates.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany.
We explore the role of molecular vibrations in the chirality-induced spin selectivity (CISS) effect in the context of charge transport through a molecular nanojunction. We employ a mixed quantum-classical approach that combines Ehrenfest dynamics for molecular vibrations with the hierarchical equations of motion method for the electronic degrees of freedom. This approach treats the molecular vibrations in a nonequilibrium manner, which is crucial for the dynamics of molecular nanojunctions.
View Article and Find Full Text PDFNat Commun
January 2025
Key Laboratory of advanced optoelectronic quantum architecture and measurements of Ministry of Education, Beijing Institute of Technology, Beijing, China.
Topolectrical circuits have emerged as a pivotal platform for realizing static topological states that are challenging to construct in other systems, facilitating the design of robust circuit devices. In addition to spatial dimensionality, synergistic engineering of both temporal and spatial degrees in circuit networks holds tremendous potential across diverse technologies, such as wireless communications, non-reciprocal electronics and dynamic signal controls with exotic space-time topology. However, the realization of space-time modulated circuit networks is still lacking due to the necessity for flexible modulation of node connections in both spatial and temporal domains.
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