Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsit...Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.展开更多
A new mixed heteropoly acid,α-H_σ[GeW_eMo_2VO_(40)].22H_2O,bas been prepared and characterized by means of ICP,potentiometric titration,IR and UV spectra, X-ray powder diffraction and thermal analysis.
The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(...The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(-1), De=3.932 g/cm^3. The final R=0.083 for 4528 non-zero reflexions. The structure of anions GeW_9V_3O_(40)~and GeW_9O_(34)~belongs to A-type.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403800 and 2023YFA1407300)the National Natural Science Foundation of China(Grant Nos.12374153,12447101,and 11974362)supported by the U.S.Department of Energy,Basic Energy Sciences(Grant No.DE-FG02-99ER45747)。
文摘Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.
基金Project supported by the National Natural Science Foundation of China.
文摘A new mixed heteropoly acid,α-H_σ[GeW_eMo_2VO_(40)].22H_2O,bas been prepared and characterized by means of ICP,potentiometric titration,IR and UV spectra, X-ray powder diffraction and thermal analysis.
文摘The complex K_3H_4GeW_9V_3O_(40)·8H_2O crystallized in a monocliinie system with space group P2, Mr=2784.67, a=11.099(3), b=16.452(4), c=13.534(4) , β=108.14(2)°, Z=2,V=2348.49 ~3, F(000):2456, μ=239.7cm^(-1), De=3.932 g/cm^3. The final R=0.083 for 4528 non-zero reflexions. The structure of anions GeW_9V_3O_(40)~and GeW_9O_(34)~belongs to A-type.
