In this paper we investigate adiabatic charge and spin pumping through interacting quantum dots using non-equilibrium Green's function techniques and the equation-of-motion method. We treat the electronic correlations inside the dot using a Hartree-Fock approximation and succeed in obtaining closed analytic expressions for the Keldysh Green's functions. These allow us to compute charge and spin currents through the quantum dot. Depending on the parameters of the quantum dot and its coupling to the reservoirs, we show that it can be found in two different regimes: the magnetic regime and the non-magnetic regime. In the magnetic regime we find a non-vanishing spin current in addition to the charge current present in both cases.
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http://dx.doi.org/10.1088/0953-8984/24/35/356001 | DOI Listing |
Mater Horiz
January 2025
School of Materials Science and Engineering, Key Laboratory of Advanced Materials and Devices for Post-Moore Chips, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China.
Realizing spin-orbit torque (SOT)-driven magnetization switching offers promising opportunities for the advancement of next-generation spintronics. However, the relatively low charge-spin conversion efficiency accompanied by an ultrahigh critical switching current density () remains a significant obstacle to the further development of SOT-based storage elements. Herein, spin absorption engineering at the ferromagnet/nonmagnet interface is firstly proposed to achieve high SOT efficiency in Pt/Co/Ir trilayers.
View Article and Find Full Text PDFChem Mater
January 2025
Department of Physics, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, U.K.
We investigate magnesium-iron pyroborate MgFeBO as a potential cathode material for rechargeable magnesium-ion batteries. Synchrotron powder X-ray diffraction and Mössbauer spectroscopy confirm its successful synthesis and iron stabilization in the high-spin Fe(II) state. Initial electrochemical testing against a lithium metal anode yields a first charge capacity near the theoretical value (147.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
Magnetization switching by charge current without a magnetic field is essential for device applications and information technology. It generally requires a current-induced out-of-plane spin polarization beyond the capability of conventional ferromagnet/heavy-metal systems, where the current-induced spin polarization aligns in-plane orthogonal to the in-plane charge current and out-of-plane spin current. Here, a new approach is demonstrated for magnetic-field-free switching by fabricating a van-der-Waals magnet and oxide FeGeTe/SrTiO heterostructure.
View Article and Find Full Text PDFSmall
January 2025
Institutes of Physical Science and Information Technology, Anhui Graphene Carbon Fiber Materials Research Center, Anhui University, Hefei, Anhui, 230601, P. R. China.
Photocatalytic hydrogen production is currently considered a clean and sustainable route to meet the energy and environmental issues. Among, heterojunction photocatalysts have been developed to improve their photocatalytic efficiency. Defect engineering of heterojunction photocatalysts is attractive due to it can perform as electron trap and change the band structure to optimize the interfacial separation rate of photogenerated electron-hole pairs.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
School of Marine Science and Engineering, Hainan University, Haikou, China.
Severe photogenerated charge carrier recombination involved in photocatalytic CO reduction leads to low photocatalytic efficiency. Here we demonstrate that a chiral hierarchical structure could facilitate charge separation in BiOBr, thus suppressing charge recombination and enhancing photocatalytic performance. Chiral helical flower-like BiOBr nanospheres were prepared a D/L-sorbitol-assisted hydrothermal process, exhibiting a 1.
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