Surface-sensitive measurements are crucial to many types of researches in condensed matter physics.However,it is difficult to obtain atomically flat surfaces of many single crystals by the commonly used mechanical cle...Surface-sensitive measurements are crucial to many types of researches in condensed matter physics.However,it is difficult to obtain atomically flat surfaces of many single crystals by the commonly used mechanical cleavage.We demonstrate that the grind-polish-sputter-anneal method can be used to obtain atomically flat surfaces on topological materials.Three types of surface-sensitive measurements are performed on CoSi(001)surface with dramatically improved quality of data.This method extends the research area of surface-sensitive measurements to hard-to-cleave alloys,and can be applied to irregular single crystals with selective crystalline planes.It may become a routine process of preparing atomically flat surfaces for surface-sensitive technologies.展开更多
The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der...The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der Waals compound VI3,revealed a structural transition above the magnetic transition but output controversial analysis on symmetry.In this paper we carried out polarized Raman scattering measurements on VI3 from 10 K to 300 K,with focus on the two Ag phonon modes at^71.1 cm^-1 and 128.4 cm-1.Our careful symmetry analysis based on the angle-dependent spectra demonstrates that the crystal symmetry can be well described by C2h rather than D3d both above and below structural phase transition.We further performed temperature-dependent Raman experiments to study the magnetism in VI3.Fano asymmetry and anomalous linewidth drop of two Ag phonon modes at low temperatures,point to a significant spin-phonon coupling.This is also supported by the softening of 71.1-cm^-1 mode above the magnetic transition.The study provides the fundamental information on lattice dynamics and clarifies the symmetry in VI3.And spin-phonon coupling existing in a wide temperature range revealed here may be meaningful in applications.展开更多
We study the influence of Cr doping on magnetic properties ofα-RuCl3 single crystals in detail.With increasing Cr content,the c-axial lattice parameter increases gradually,implying that the Cr doping may weaken the i...We study the influence of Cr doping on magnetic properties ofα-RuCl3 single crystals in detail.With increasing Cr content,the c-axial lattice parameter increases gradually,implying that the Cr doping may weaken the interlayer interactions.The magnetism of Ru1-xCrxCl3 single crystals evolves from a long-range AFM order to a possible spin-glass state with Cr doping.The appearance of a possible spin-glass state can be explained by the introduction of FM interaction by Cr3+ions,which competes with the AFM interaction between Ru3+ions.Noreover,the larger magnetic moment of Cr3+ion with S=3/2 than Ru3+ion with Jeff=1/2 also results in a monotonic increase of the effective moment of Ru1-xCrxCl3 single crystal.展开更多
基金Project supported by the Science Fund from the Ministry of Science and Technology of China(Grant Nos.2016YFA0401000,2016YFA0300600,2016YFA0302400,2016YFA0300504,and 2017YFA0302901)the National Natural Science Foundation of China(Grant Nos.11622435,U1832202,11474340,11822412,11574371,11674369,11574394,11774423,and 11774399)+4 种基金the Fund from the Chinese Academy of Sciences(Grant Nos.QYZDB-SSW-SLH043,XDB07000000,and XDB28000000)the Science Challenge Project,China(Grant No.TZ2016004)the K C Wong Education Foundation,China(Grant No.GJTD-2018-01)the Beijing Natural Science Foundation,China(Grant No.Z180008),the Fund from the Beijing Municipal Science and Technology Commission,China(Grant Nos.Z171100002017018,Z181100004218005,and Z181100004218001)the Fundamental Research Funds for the Central Universities,China,and the Research Funds of Renmin University of China(Grant Nos.15XNLQ07,18XNLG14,and 19XNLG17).
文摘Surface-sensitive measurements are crucial to many types of researches in condensed matter physics.However,it is difficult to obtain atomically flat surfaces of many single crystals by the commonly used mechanical cleavage.We demonstrate that the grind-polish-sputter-anneal method can be used to obtain atomically flat surfaces on topological materials.Three types of surface-sensitive measurements are performed on CoSi(001)surface with dramatically improved quality of data.This method extends the research area of surface-sensitive measurements to hard-to-cleave alloys,and can be applied to irregular single crystals with selective crystalline planes.It may become a routine process of preparing atomically flat surfaces for surface-sensitive technologies.
基金Project supported by the Science Fund from the Ministry of Science and Technology of China(Grant Nos.2017YFA0302904 and 2016YFA0300504)the National Natural Science Foundation of China(Grant Nos.11774419,U1932215,11774423,and 11822412)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Renmin University of China(RUC)(Grant Nos.15XNLQ07,18XNLG14,and 19XNLG17).
文摘The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der Waals compound VI3,revealed a structural transition above the magnetic transition but output controversial analysis on symmetry.In this paper we carried out polarized Raman scattering measurements on VI3 from 10 K to 300 K,with focus on the two Ag phonon modes at^71.1 cm^-1 and 128.4 cm-1.Our careful symmetry analysis based on the angle-dependent spectra demonstrates that the crystal symmetry can be well described by C2h rather than D3d both above and below structural phase transition.We further performed temperature-dependent Raman experiments to study the magnetism in VI3.Fano asymmetry and anomalous linewidth drop of two Ag phonon modes at low temperatures,point to a significant spin-phonon coupling.This is also supported by the softening of 71.1-cm^-1 mode above the magnetic transition.The study provides the fundamental information on lattice dynamics and clarifies the symmetry in VI3.And spin-phonon coupling existing in a wide temperature range revealed here may be meaningful in applications.
基金Supported by the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(Grant Nos.15XNLQ07,18XNLG14,and 19XNLG17)。
文摘We study the influence of Cr doping on magnetic properties ofα-RuCl3 single crystals in detail.With increasing Cr content,the c-axial lattice parameter increases gradually,implying that the Cr doping may weaken the interlayer interactions.The magnetism of Ru1-xCrxCl3 single crystals evolves from a long-range AFM order to a possible spin-glass state with Cr doping.The appearance of a possible spin-glass state can be explained by the introduction of FM interaction by Cr3+ions,which competes with the AFM interaction between Ru3+ions.Noreover,the larger magnetic moment of Cr3+ion with S=3/2 than Ru3+ion with Jeff=1/2 also results in a monotonic increase of the effective moment of Ru1-xCrxCl3 single crystal.
