查看更多>>摘要：Heat in solids can be transported by various quasiparticles,making low-temperature heat transport a powerful tool for probing charge-neutral excitations in quantum materials.In recent years,ultralow-temperature heat transport has been instrumental in detecting exotic excitations in quantum spin liquids(QSLs).A non-zero residual thermal conductivity,κ0/T,serves as compelling evidence for the presence of itinerant spinons and the gapless nature of a disordered state.Additionally,the thermal Hall effect(THE)in QSLs can arise from contributions by spinons or Majorana fermions.In this review,we summarize key thermal conductivity findings from various QSL candidates,focusing on the role of spinons in both heat transport and phonon scattering.We also examine different experimental observations and the underlying mechanisms of THE in QSL candidates with three-dimensional pyrochlore structures,as well as two-dimensional honeycomb and triangular lattices.This review offers valuable insights and guidance for understanding ultralow-temperature heat transport in QSLs.
查看更多>>摘要：As a typical two-dimensional frustrated quantum magnet,the triangular-lattice antiferromagnet exhibits a series of exotic states from the complicated interplay of the lattice,spin,electron,and orbit with quantum and thermal fluctuations.From the ground state of a triangular-lattice Heisenberg antiferromagnet with coplanar 120° ordering,a series of magnetization anomalies can manifest under a magnetic field,such as the 1/3 magnetization plateau(Ms/3)and umbrella-shaped phase.This Ms/3 plateau state is recognized as an up-up-down structure stabilized by the quantum effect.By surveying theoretical research and experimental measurements on triangular-lattice antiferromagnets,this review article describes the current understanding of the magnetic properties of triple-perovskite antiferromagnets A3MB2O9(A=Ba,Ca,and Sr;M=Co,Ni,and Mn;B=Sb,Nb).Through examining both the bulk properties and spin dynamics,fascinating insights into the quantum effect on the triangular lattice are discussed.
查看更多>>摘要：Electromagnetic wave-absorbing materials play a crucial role in modern electronics,particularly in stealth and communication technologies.Carbon-based materials demonstrate considerable potential for the development and use of effective wave-absorbing substances,attributed to their complex structure,lightweight nature,excellent corrosion resistance,and affordability.Notably,nitrogen-doped carbon-based two-dimensional(2D)materials exhibit a more pronounced depletion effect on electromagnetic waves owing to their increased specific surface area and numerous polarization states.This article presents the successful synthesis of nitrogen-doped carbon(NC)2D flakes using a hydrothermal method.In addition,single Fe atoms were successfully incorporated onto their surfaces,forming Fe@NC.The wave-absorbing capabilities of the Fe@NC samples were considerably improved,achieving a minimum reflection loss(RLmin)of-69.22 dB at 11.48 GHz and an effective absorption bandwidth of 5.79 GHz.The enhancement in electromagnetic wave absorption is attributed to the synergistic effects of magnetic loss,relaxation processes,dipole polarization,and electrical conduction loss.The successful synthesis of Fe@NC opens up new avenues for the development of atomically dispersed wave-absorbing materials.
查看更多>>摘要：Metal contacts to two-dimensional(2D)semiconductors are crucial for determining the electrical performance of electronic devices.However,traditional three-dimensional metal deposition processes cause damage to 2D semiconductors and considerable Fermi-level-pinning effects.In this study,a hexagonal boron nitride(h-BN)-assisted transfer method was proposed for transferring metal contacts to few-layered InSe for fabricating 2D functional electronic devices.Using the transferred Pt electrodes as the contact,p-type dominated ambipolar conduction behavior with the hole Schottky barrier height(SBH)approaching 0 meV was observed in field-effect transistors(FETs)comprising multilayered InSe.Based on this phenomenon,several InSe homojunctions were fabricated using a dual-gate modulating method such as p-p,n-n,p-n,and n-p.For InSe p-n homojunctions,a current rectification ratio of over 104 and optoelectronic detection capabilities were achieved.Furthermore,a complementary metal-oxide-semiconductor(CMOS)inverter with an ultra-high voltage gain exceeding 60 at VDD=-1V was fabricated.The proposed h-BN-assisted metal contact transfer method can be easily extended to other 2D semiconductors for fabricating complementary electronic and optoelectronic devices.
查看更多>>摘要：Most phages—viruses infecting prokaryotes—inject their genomes via a tail structure.The central tail tube,composed of tail tube protein(TTP),typically forms conserved hexameric or trimeric rings.In this paper,we report a novel pentameric TTP assembly,solved by cryo-electron microscopy(cryo-EM)at 3.5 Å and 3.7 Å resolution.Structural analysis reveals a highly negatively charged inner surface of this pentameric tube.Key residues in the loop connecting β3 and β4 strands are crucial for pentameric ring formation.Mismatches in interactions between stacked layers can induce curvature in the tube.The cryo-EM structure of the TTP polymer at the tube's end shows that β-strands spanning amino acids 27-65 shift toward the central tunnel,potentially obstructing the passage of the phage genome.This study provides new structural insights into a unique TTP assembly,enhancing our understanding of phage assembly processes.
查看更多>>摘要：Detecting dark matter remains one of the most challenging problems in modern physics.We propose a method to detect the coupling of ultralight scalar dark matter to quarks and gluons,as well as the coupling of ultralight axion dark matter to gluons,using long-baseline atom interferometers.Interactions between ultralight scalar and axion dark matter with quarks and gluons can induce oscillations in nuclear charge radii,consequently causing oscillations in atomic transition frequencies.We calculate the differential phase shift produced by these dark matter interactions in long-baseline atom interferometers,presenting constraints on the scalar dark matter coupling parameters dg and d(m),as well as on the axion dark matter coupling parameter 1/fa.Our results are anticipated to improve existing bounds and complement bounds from other experiments.
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