Magnetism and spin-orbit coupling are two fundamental and interconnected properties of oxide materials,that can give rise to various topological transport phenomena,including anomalous Hall and anomalous Nernst effect...Magnetism and spin-orbit coupling are two fundamental and interconnected properties of oxide materials,that can give rise to various topological transport phenomena,including anomalous Hall and anomalous Nernst effects.These transport responses can be significantly enhanced by designing an electronic structure with a large Berry curvature.In this context,rocksalt-ordered double perovskites(DP),denoted as A2BB’O6,with two distinct transition metal sites are very powerful platforms for exploration and research.In this work,we present a comprehensive study based on the intrinsic anomalous transport in cubic and tetragonal stable DP compounds with 3d-4d/5d elements.Our findings reveal that certain DP compounds show a large anomalous Hall effect,displaying topological band crossings in the proximity of the Fermi energy.展开更多
Most topological insulators(TIs)discovered today in spinful systems can be transformed from topological semimetals(TSMs)with vanishing bulk gap via introducing the spin-orbit coupling(SOC),which manifests the intrinsi...Most topological insulators(TIs)discovered today in spinful systems can be transformed from topological semimetals(TSMs)with vanishing bulk gap via introducing the spin-orbit coupling(SOC),which manifests the intrinsic links between the gapped topological insulator phases and the gapless TSMs.Recently,we have discovered a family of TSMs in time-reversal invariant spinless systems,which host butterfly-like nodal-lines(NLs)consisting of a pair of identical concentric intersecting coplanar ellipses(CICE).In this Communication,we unveil the intrinsic link between this exotic class of nodal-line semimetals(NLSMs)and a Z_(4)=2 topological crystalline insulator(TCI),by including substantial SOC.We demonstrate that in three space groups(i.e.,Pbam(No.55),P4/mbm(No.127),and P4_(2)/mbc(No.135)),the TCI supports a fourfold Dirac fermion on the(001)surface protected by two glide symmetries,which originates from the intertwined drumhead surface states of the CICE NLs.The higher order topology is further demonstrated by the emergence of one-dimensional helical hinge states,indicating the discovery of a higher order topological insulator protected by a glide symmetry.展开更多
基金This work is financially supported by the European Research Council(ERC Advanced Grant no.742068‘TOPMAT’)We also acknowledge funding by the DFG through SFB 1143(project ID.247310070)+3 种基金the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter ct.qmat(EXC2147,project ID.39085490)M.G.V.and I.R.thanks support from the Spanish Ministerio de Ciencia e Innovacion(grant PID2019-109905GB-C21)European Research Council(ERC)grant agreement no.101020833M.G.V.and C.F.acknowledge support by the Deutsche Forschungsge-meinschaft(DFG,German Research Foundation)-FOR 5249(QUAST).
文摘Magnetism and spin-orbit coupling are two fundamental and interconnected properties of oxide materials,that can give rise to various topological transport phenomena,including anomalous Hall and anomalous Nernst effects.These transport responses can be significantly enhanced by designing an electronic structure with a large Berry curvature.In this context,rocksalt-ordered double perovskites(DP),denoted as A2BB’O6,with two distinct transition metal sites are very powerful platforms for exploration and research.In this work,we present a comprehensive study based on the intrinsic anomalous transport in cubic and tetragonal stable DP compounds with 3d-4d/5d elements.Our findings reveal that certain DP compounds show a large anomalous Hall effect,displaying topological band crossings in the proximity of the Fermi energy.
基金The work at CSUN was supported by NSF-Partnership in Research and Education in Materials(PREM)Grant No.DMR-1828019H.L.acknowledges the support by the Ministry of Science and Technology(MOST)in Taiwan under grant number MOST 109-2112-M-001-014-MY3+2 种基金The work of J.L.M.has been supported by Spanish Science Ministry grant PGC2018-094626-B-C21(MCIU/AEI/FEDER,EU)and Basque Government grant IT979-16M.G.V.thanks support from DFG INCIEN2019-000356 from Gipuzkoako Foru AldundiaM.G.V.and M.I.acknowledges the Spanish Ministerio de Ciencia e Innovacion(grant number PID2019-109905GB-C21).
文摘Most topological insulators(TIs)discovered today in spinful systems can be transformed from topological semimetals(TSMs)with vanishing bulk gap via introducing the spin-orbit coupling(SOC),which manifests the intrinsic links between the gapped topological insulator phases and the gapless TSMs.Recently,we have discovered a family of TSMs in time-reversal invariant spinless systems,which host butterfly-like nodal-lines(NLs)consisting of a pair of identical concentric intersecting coplanar ellipses(CICE).In this Communication,we unveil the intrinsic link between this exotic class of nodal-line semimetals(NLSMs)and a Z_(4)=2 topological crystalline insulator(TCI),by including substantial SOC.We demonstrate that in three space groups(i.e.,Pbam(No.55),P4/mbm(No.127),and P4_(2)/mbc(No.135)),the TCI supports a fourfold Dirac fermion on the(001)surface protected by two glide symmetries,which originates from the intertwined drumhead surface states of the CICE NLs.The higher order topology is further demonstrated by the emergence of one-dimensional helical hinge states,indicating the discovery of a higher order topological insulator protected by a glide symmetry.
