Photoemission experiments have shown that Bi2Se3 is a topological insulator. By controlled doping, we have obtained crystals of Bi2Se3 with nonmetallic conduction. At low temperatures, we uncover a novel type of magnetofingerprint signal which involves the spin degrees of freedom. Given the mm-sized crystals, the observed amplitude is 200-500x larger than expected from universal conductance fluctuations. The results point to very long phase-breaking lengths in an unusual conductance channel in these nonmetallic samples. We discuss the nature of the in-gap conducting states and their relation to the topological surface states.
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http://dx.doi.org/10.1103/PhysRevLett.103.246601 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
The chiral edge current is the boundary manifestation of the Chern number of a quantum anomalous Hall (QAH) insulator. The van der Waals antiferromagnet MnBiTe is theorized to be a QAH in odd-layers but has shown Hall resistivity below the quantization value at zero magnetic field. Here, we perform scanning superconducting quantum interference device (sSQUID) microscopy on these seemingly failed QAH insulators to image their current distribution.
View Article and Find Full Text PDFNano Lett
January 2025
IBM Research─Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
The inhomogeneous magnetic stray field of micromagnets has been extensively used to manipulate electron spin qubits. By means of micromagnetic simulations and scanning superconducting quantum interference device microscopy, we show that the polycrystallinity of the magnet and nonuniform magnetization significantly impact the stray field and corresponding qubit properties. The random orientation of the crystal axis in polycrystalline Co magnets alters the qubit frequencies by up to 0.
View Article and Find Full Text PDFACS Nano
January 2025
Center for Terahertz Waves and School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
The physical picture for photocurrent injection and coherent control in intrinsic graphene under two-color laser excitation remains obscure. Previously, photocurrent injection of intrinsic graphene was attributed to the quantum interference between two electronic transition pathways of single-photon and two-photon absorptions as well as layer-to-layer coupling. Here, we show that quantum interference between stimulated electronic Raman scattering and single-photon absorption plays a very important role in contributing to the total photocurrent, while interlayer coupling does not sufficiently affect the photocurrent injection, which is in contrast to the previous interpretation of the experimental results on photocurrent injection and coherent control.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
The quantum transition state framework was developed to calculate the reaction path-resolved scattering matrix for atom-diatom reactions in hyperspherical (APH) coordinates. This approach allows for simply and directly calculating the reaction path-resolved scattering matrix, especially when the encircling reaction path is negligible. It could be used to determine the reactivities of specific pathways in a chemical reaction, providing insights into phenomena such as geometric phase effects.
View Article and Find Full Text PDFChem Asian J
January 2025
Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter, State Key Laboratory of Structural Chemistry, CHINA.
Molecular electronics represent the cutting-edge and interdisciplinary effort on the future miniaturization of electronic circuits. Benefiting from synthetic chemistry and theoretical insights, molecular circuit studies have promoted devices with increasingly complicated structures. Especially, the evolution of conductive backbones from simple chain-shape single-channel configurations to complex multi-channel architectures marks a pivotal progression.
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