1,118 research outputs found
Competing Magnetic Orderings and Tunable Topological States in Two-Dimensional Hexagonal Organometallic Lattices
The exploration of topological states is of significant fundamental and
practical importance in contemporary condensed matter physics, for which the
extension to two-dimensional (2D) organometallic systems is particularly
attractive. Using first-principles calculations, we show that a 2D hexagonal
triphenyl-lead lattice composed of only main group elements is susceptible to a
magnetic instability, characterized by a considerably more stable
antiferromagnetic (AFM) insulating state rather than the topologically
nontrivial quantum spin Hall state proposed recently. Even though this AFM
phase is topologically trivial, it possesses an intricate emergent degree of
freedom, defined by the product of spin and valley indices, leading to Berry
curvature-induced spin and valley currents under electron or hole doping.
Furthermore, such a trivial band insulator can be tuned into a topologically
nontrivial matter by the application of an out-of-plane electric field, which
destroys the AFM order, favoring instead ferrimagnetic spin ordering and a
quantum anomalous Hall state with a non-zero topological invariant. These
findings further enrich our understanding of 2D hexagonal organometallic
lattices for potential applications in spintronics and valleytronics.Comment: 9 pages, 8 figure
Sound Demixing Challenge 2023 Music Demixing Track Technical Report: TFC-TDF-UNet v3
In this report, we present our award-winning solutions for the Music Demixing
Track of Sound Demixing Challenge 2023. First, we propose TFC-TDF-UNet v3, a
time-efficient music source separation model that achieves state-of-the-art
results on the MUSDB benchmark. We then give full details regarding our
solutions for each Leaderboard, including a loss masking approach for
noise-robust training. Code for reproducing model training and final
submissions is available at github.com/kuielab/sdx23.Comment: 5 pages, 4 table
Space Vector Modulation Technique for Reducing Harmonics in Current with Zero Common-Mode Voltage for Two-Parallel Three-Level Converters
A zero common-mode voltage (ZCMV) modulation has the advantage of reducing electromagnetic interference (EMI) and a feature that hardly generates a zero- sequence circulating current (ZSCC) in converters operating in parallel. However, this modulation has a critical issue related to the increase in harmonics in the phase current due to the limitation of using voltage vectors generating ZCMV. Thus, this paper proposes an optimal space vector modulation (SVM) technique for two-parallel three-level converters to reduce the harmonics increased by using the ZCMV PWM. The creation of virtual voltage vectors (VVVs) using vector synthesis based on the ZCMV PWM is addressed. Accordingly, new small regions in each sector of the SVM are defined in consideration with the nearest three voltage vectors, including the virtual vectors. In addition, PWM sequences for each region and dwell time for each voltage vector are also determined. Optimal vector utilization of the proposed ZCMV SVM can further reduce the current harmonics. The performance comparison between the proposed ZCMV SVM and existing methods are presented in simulation and experimental results
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