Optical and photoemission experiments reveal unexpected spectral signatures of one-dimensional band insulators. In the model compound (NbSe (4))3I the optical conductivity decays as a power law sigma(1)(omega) approximately omega(-4.25) above a sharp gap edge. Photoemission observes both the valence and a shadow band, produced by a commensurate superstructure. We identify an optical and photoemission band gap consistent with other measurements but much smaller than the energy scale defined by the dispersion of the band peak in the photoemission spectra.
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http://dx.doi.org/10.1103/PhysRevLett.84.1272 | DOI Listing |
Adv Mater
December 2024
Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, P. R. China.
By manipulating their asymmetric electronic spin states, the unique electronic structures and unsaturated coordination environments of single atoms can be effectively harnessed to control their magnetic properties. In this research, the first investigation is presented into the regulation of magnetic properties through the electronic spin states of single atoms. Magnetic single-atom one-dimensional materials, M-N-C/ZrO (M = Fe, Co, Ni), with varying electronic spin states, are design and synthesize based on the electronic orbital structure model.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China.
Quasi-one-dimensional (Q1D) systems are inherently unfavorable for superconductivity due to electronic instabilities and significant quantum fluctuations. This has led to a half-century-long pursuit of strong and robust Q1D superconductors. Herein, we propose an effective multiorbital chain approach that utilizes the interorbital self-doping to not only suppress the instability but also to position the Fermi level near the band edges.
View Article and Find Full Text PDFNatl Sci Rev
December 2024
School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
Because of the lack of translational symmetry, calculating the energy spectrum of an incommensurate system has always been a theoretical challenge. Here, we propose a natural approach to generalize energy band theory to incommensurate systems without reliance on the commensurate approximation, thus providing a comprehensive energy spectrum theory of incommensurate systems. Except for a truncation-dependent weighting factor, the formulae of this theory are formally almost identical to that of Bloch electrons, making it particularly suitable for complex incommensurate structures.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
School of Information Science and Technology, Northwest University, Xi'an 710127, China.
Designing and discovering superior type-II band alignment are crucial for advancing optoelectronic device technologies. Here, we employ first-principles calculations to investigate the evolution of band edges in monolayer MoS, boron phosphide (BP), and MoS/BP heterostructures before and after their rolling into nanotubes. Our research results indicate that the intrinsic MoS/BP vertical heterostructures exhibit a type-II direct bandgap, but this feature is not robust under strain.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
The solar sector is shifting towards lead-free, inorganic cubic halide perovskites due to their superior structural, electronic, and optoelectronic properties. This study uses density functional theory (DFT) to examine the structural, electronic, and optical properties of XSnBr (X = Cs, Rb, K, Na) and assesses their photovoltaic performance through the Solar Cell Capacitance Simulator - One Dimensional (SCAPS-1D). The results show each material has a direct band gap at the Γ-point, low optical losses, and high absorption, making them promising for solar and optoelectronic applications.
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