Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes...Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Sr_(n+1)IrnO_(3n+1)(n=1,2)is doped with carriers.While electron-doped Sr_(n+1)IrnO_(3n+1)(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr_(3)Ir_(2)O_(7)single crystals[Sr_3(Ir_(1-x)Fe_x)_(2)O_(7)]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr_(3)Ir_(2)O_(7)have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr_(3)Ir_(2)O_(7).Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr_(3)Ir_(2)O_(7),thereby offering a powerful strategy to modulate MIT in this material system.展开更多
Ruddlesden-Popper iridate Sr_(3)Ir_(2)O_(7)is a spin-orbit coupled Mott insulator.Hole doped Sr_(3)Ir_(2)O_(7)provides an ideal platform to study the exotic quantum phenomena that occur near the metal-insulator transi...Ruddlesden-Popper iridate Sr_(3)Ir_(2)O_(7)is a spin-orbit coupled Mott insulator.Hole doped Sr_(3)Ir_(2)O_(7)provides an ideal platform to study the exotic quantum phenomena that occur near the metal-insulator transition(MIT)region.Rh substitution of Ir is an effective method to induce hole doping into Sr_(3)Ir_(2)O_(7).However,the highest doping level reported in Sr_(3)(Ir_(1-x)Rh_(x))_(2)O_(7)single crystals was only around 3%,which is far from the MIT region.In this paper,we report the successful growth of single crystals of Sr3(Ir_(1-x)Rh_(x))_(2)O_(7)with a doping level of~9%.The samples have been fully characterized,demonstrating the high quality of the single crystals.Transport measurements have been carried out,confirming the tendency of MIT in these samples.The electronic structure has also been examined by angle-resolved photoemission spectroscopy(ARPES)measurements.Our results establish a platform to investigate the heavily hole doped Sr_(3)Ir_(2)O_(7) compound,which also provide new insights into the MIT with hole doping in this material system.展开更多
The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as disti...The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as distinct electronic structures in both bulk and surface states of the material.An interesting next step is to manipulate the electronic states in this system.Here,we report angle-resolved photoemission spectroscopy(ARPES)evidence for a surface-induced orbitalselective band reconstruction in Cs V_(3)Sb_(5).A significant energy shift of the electron-like band aroundΓand a moderate energy shift of the hole-like band around M are observed as a function of time.This evolution is reproduced in a much shorter time scale by in-situ annealing of the Cs V_(3)Sb_(5) sample.Orbital-resolved density functional theory(DFT)calculations reveal that the momentum-dependent band reconstruction is associated with different orbitals for the bands aroundΓand M,and the time-dependent evolution points to the change of sample surface that is likely caused by the formation of Cs vacancies on the surface.Our results indicate the possibility of orbital-selective control of the band structure via surface modification,which may open a new avenue for manipulating exotic phenomena in this material system,including superconductivity.展开更多
Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism an...Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism and strong electronic correlations—two essential ingredients for unconventional superconductivity,are absent in this V-based Kagome metal.CsCr_(3)Sb_(5) is a newly discovered Cr-based parallel of CsV_(3)Sb_(5),in which magnetism appears with charge density wave and superconductivity at different temperature and pressure regions.Enhanced electronic correlations are also suggested by theoretical proposals due to the calculated flat bands.Here,we report angle-resolved photoemission measurements and firstprinciples calculations on this new material system.Electron energy bands and the associated orbitals are resolved.Flat bands are observed near the Fermi level.Doping dependent measurements on Cs(V_(1-x)Cr_(x))_(3)Sb_(5) reveal a gradually enhanced band renormalization from CsV_(3)Sb_(5) to CsCr_(3)Sb_(5),accompanied by distinct spatial symmetry breaking states in the phase diagram.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12074358)the National Key Research and Development Program of China(Grant No.2024YFA1408103)+2 种基金the International Partnership Program of the Chinese Academy of Sciences(Grant No.123GJHZ2022035MI)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000015)。
文摘Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Sr_(n+1)IrnO_(3n+1)(n=1,2)is doped with carriers.While electron-doped Sr_(n+1)IrnO_(3n+1)(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr_(3)Ir_(2)O_(7)single crystals[Sr_3(Ir_(1-x)Fe_x)_(2)O_(7)]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr_(3)Ir_(2)O_(7)have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr_(3)Ir_(2)O_(7).Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr_(3)Ir_(2)O_(7),thereby offering a powerful strategy to modulate MIT in this material system.
基金supported by the USTC start-up fundthe National Natural Science Foundation of China(Grant Nos.12074358 and 12004363)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.WK3510000008 and WK2030000035)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Contract No.DEAC02-76SF00515。
文摘Ruddlesden-Popper iridate Sr_(3)Ir_(2)O_(7)is a spin-orbit coupled Mott insulator.Hole doped Sr_(3)Ir_(2)O_(7)provides an ideal platform to study the exotic quantum phenomena that occur near the metal-insulator transition(MIT)region.Rh substitution of Ir is an effective method to induce hole doping into Sr_(3)Ir_(2)O_(7).However,the highest doping level reported in Sr_(3)(Ir_(1-x)Rh_(x))_(2)O_(7)single crystals was only around 3%,which is far from the MIT region.In this paper,we report the successful growth of single crystals of Sr3(Ir_(1-x)Rh_(x))_(2)O_(7)with a doping level of~9%.The samples have been fully characterized,demonstrating the high quality of the single crystals.Transport measurements have been carried out,confirming the tendency of MIT in these samples.The electronic structure has also been examined by angle-resolved photoemission spectroscopy(ARPES)measurements.Our results establish a platform to investigate the heavily hole doped Sr_(3)Ir_(2)O_(7) compound,which also provide new insights into the MIT with hole doping in this material system.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.WK3510000008 and WK3510000012)USTC start-up fund+3 种基金supported by the UC Santa Barbara NSF Quantum Foundry funded via the Q-AMASE-i program under award DMR-1906325the NSF Materials Research Science and Engineering Center at UC Santa Barbara(DMR-1720256)support from the California Nano Systems Institute through the Elings Fellowship programsupported by the National Science Foundation Graduate Research Fellowship Program under Grant No.DGE1650114。
文摘The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as distinct electronic structures in both bulk and surface states of the material.An interesting next step is to manipulate the electronic states in this system.Here,we report angle-resolved photoemission spectroscopy(ARPES)evidence for a surface-induced orbitalselective band reconstruction in Cs V_(3)Sb_(5).A significant energy shift of the electron-like band aroundΓand a moderate energy shift of the hole-like band around M are observed as a function of time.This evolution is reproduced in a much shorter time scale by in-situ annealing of the Cs V_(3)Sb_(5) sample.Orbital-resolved density functional theory(DFT)calculations reveal that the momentum-dependent band reconstruction is associated with different orbitals for the bands aroundΓand M,and the time-dependent evolution points to the change of sample surface that is likely caused by the formation of Cs vacancies on the surface.Our results indicate the possibility of orbital-selective control of the band structure via surface modification,which may open a new avenue for manipulating exotic phenomena in this material system,including superconductivity.
基金the support by the National Natural Science Foundation of China(Grant Nos.52273309,and 52261135638)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000015)+10 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the International Partnership Program of the Chinese Academy of Sciences(Grant No.123GJHZ2022035MI)the support by the National Key R&D Program of China(Grant No.2023YFA1406304)the National Natural Science Foundation of China(Grant No.U2032208)the support by the National Natural Science Foundation of China(Grant Nos.12474158,12234017,and 12488101)the National Key R&D Program of China(Grant No.2024YFA1408103)Anhui Initiative in Quantum Information Technologies(Grant No.AHY170000)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)Beijing Institute of Technology was supported by the National Key R&D Program of China(Grant Nos.2020YFA0308800,and 2022YFA1403400)the National Natural Science Foundation of China(Grant No.92065109)the Beijing Natural Science Foundation(Grant Nos.Z210006,Z190006)。
文摘Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism and strong electronic correlations—two essential ingredients for unconventional superconductivity,are absent in this V-based Kagome metal.CsCr_(3)Sb_(5) is a newly discovered Cr-based parallel of CsV_(3)Sb_(5),in which magnetism appears with charge density wave and superconductivity at different temperature and pressure regions.Enhanced electronic correlations are also suggested by theoretical proposals due to the calculated flat bands.Here,we report angle-resolved photoemission measurements and firstprinciples calculations on this new material system.Electron energy bands and the associated orbitals are resolved.Flat bands are observed near the Fermi level.Doping dependent measurements on Cs(V_(1-x)Cr_(x))_(3)Sb_(5) reveal a gradually enhanced band renormalization from CsV_(3)Sb_(5) to CsCr_(3)Sb_(5),accompanied by distinct spatial symmetry breaking states in the phase diagram.
