We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction rev...We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,respectively.The temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration.We find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap feature.The high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 K.No magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.展开更多
Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crysta...Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crystal growth of 166-type kagome magnetic materials,including HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6),GdMn_(6)Sn_(6)and GdV_(6)Sn_(6),by using the flux method with Sn as the flux.Among them,HfMn_(6)Sn_(6)and ZrMn_(6)Sn_(6)single crystals were grown for the first time.X-ray diffraction measurements reveal that all four samples crystallize in HfFe6Ge6-type hexagonal structure with space group P6/mmm.All samples show metallic behavior from temperature dependence of resistivity measurements,and the dominant carrier is hole,except for GdV6Sn6 which is electron dominated.All samples have magnetic order with different transition temperatures,HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6)and GdV_(6)Sn_(6)are antiferromagnetic with TN of 541 K,466 K and 4 K respectively,while GdMn_(6)Sn_(6)is ferrimagnetic with the critical temperature of about 470 K.This study will enrich the research platform of magnetic kagome materials and help explore the novel quantum phenomena in these interesting materials.The dataset of specific crystal structure parameters for HfMn_(6)Sn_(6)are available in Science Data Bank,with the link.展开更多
We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are succ...We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are success- fully obtained. The measurement of temperature dependence of electricaJ resistivity p（T） in both normal and superconducting states indicates a quasi-two-dimensional electronic state in contrast to that of polycrystalline samples. Specific heat C（T） measurement reveals a bulk superconductivity with Tc ≈ 3.75K and a specific heat jump ratio of 1.42. All these results are in agreement with a moderately electron-phonon coupled, type-g Bardeen-Cooper-Schrieffer superconductor.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
Bi2Te3single crystals were prepared by the solid-state reaction method. The effect of the vacuum on the growth of Bi2Te3 single crystals was studied with varying the oxygen content by controlling the air pressure in t...Bi2Te3single crystals were prepared by the solid-state reaction method. The effect of the vacuum on the growth of Bi2Te3 single crystals was studied with varying the oxygen content by controlling the air pressure in the silica tube. High quality Bi2Te3 single crystals have been obtained and there is no influence on the growth by an extremely small amount of oxygen in a high vacuum at 1.0 × 10^-3Pa. As the air pressure is increased at 1.0 × 10^-2Pa, oxygen only mainly impacts on the growth of the surface for the prepared samples. Micron-sized rod-like structure and flower-like clusters are observed on the surface. For the samples prepared at 1.0 × 10^-1Pa, x-ray diffraction data show that the yellow part on the surface is Bi2TeO5, while the Bi2Te3 single crystal is still the major phase as the inside part. More interestingly, various crystal morphologies are observed by scanning electron microscope for Bi2Te3 near the boundary between Bi2Te3 and Bi2TeO5.Possible growth mechanisms for Bi2Te3 with different morphologies are discussed in detail.展开更多
High-quality single crystals of A-site ordered perovskite oxides CaCu3Ru4O12 were synthesized by flux method with Cu O serving as a flux. The typical size of these single crystals was around 1 × 1 × 1 mm^3 a...High-quality single crystals of A-site ordered perovskite oxides CaCu3Ru4O12 were synthesized by flux method with Cu O serving as a flux. The typical size of these single crystals was around 1 × 1 × 1 mm^3 and the lattice constant was determined to be 7.430 ± 0.0009 ？A by using x-ray single crystal diffraction. The surfaces of the samples were identified to be（100） surface. The high quality of the single crystal samples was confirmed by the rocking curve data which have a full width at half maximum of approximately 0.02 degree. The x-ray photoelectron spectroscopy measurement was performed and the temperature-dependent specific heat, magnetic susceptibility, and electric resistivity were measured along the [100]direction of the single crystals. All these measurements showed that the physical properties of Ca Cu3Ru4O12 single crystals are similar to that of polycrystals. However, the single crystals have a lower Curie susceptibility tail and a smaller residual resistivity than polycrystals, which indicates that the amount of paramagnetic impurities can be controlled by tuning the number of defects in CaCu3Ru4O12 samples.展开更多
We investigate the temperature field variation in the growth region of a diamond crystal in a sealed cell during the whole process of crystal growth by using the temperature gradient method （TGM） at high pressure an...We investigate the temperature field variation in the growth region of a diamond crystal in a sealed cell during the whole process of crystal growth by using the temperature gradient method （TGM） at high pressure and high temperature （HPHT）. We employ both the finite element method （FEM） and in situ experiments. Simulation results show that the temperature in the center area of the growth cell continues to decrease during the process of large diamond crystal growth. These results are in good agreement with our experimental data, which demonstrates that the finite element model can successfully predict the temperature field variations in the growth cell. The FEM simulation will be useful to grow larger high-quality diamond crystal by using the TGM. Furthermore, this method will be helpful in designing better cells and improving the growth process of gem-quality diamond crystal.展开更多
To elucidate the regulation mechanism of catalyst geometry structure to diamond growth,we establish three catalyst modes with different structures.The simulation results show that with the decrease of the protruding h...To elucidate the regulation mechanism of catalyst geometry structure to diamond growth,we establish three catalyst modes with different structures.The simulation results show that with the decrease of the protruding height of the catalyst,the low-temperature region gradually moves toward the center of the catalyst,which causes the distribution characteristics of the temperature and convection field in the catalyst to change.The temperature difference in vertical direction of the catalyst decreases gradually and increases in the horizontal direction,while the catalyst convection velocity has the same variation regularity in the corresponding directions.The variation of temperature difference and convection velocity lead the crystal growth rate in different crystal orientations to change,which directly affects the crystal morphology of the synthetic diamond.The simulation results are consistent with the experimental results,which shows the correctness of the theoretical rational analysis.This work is expected to be able to facilitate the understanding of catalyst structure regulation mechanism on diamond morphology and the providing of an important theoretical basis for the controllable growth of special crystal shape diamond under HPHT process.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2017YFA0302901)the Strategic Priority Research Program,the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No.XDB33010100)+3 种基金the National Natural Science Foundation of China (Grant Nos.12134018,11921004,and 11634015)the Foundation of Quantum Science Center of Guangdong–Hong Kong–Macao Greater Bay Area,China (Grant No.QD2301005)the Postdoctoral Science Foundation of China (Grant No.2021M693370)the Synergetic Extreme Condition User Facility (SECUF)。
文摘We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,respectively.The temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration.We find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap feature.The high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 K.No magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.
基金the Beijing Natural Science Founda-tion(Grant No.Z210006)the National Key Research and De-velopment Program of China(Grant Nos.2022YFA1403400 and 2020YFA0308800)the Beijing National Labora-tory for Condensed Matter Physics(Grant No.2023BNL-CMPKF007).
文摘Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crystal growth of 166-type kagome magnetic materials,including HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6),GdMn_(6)Sn_(6)and GdV_(6)Sn_(6),by using the flux method with Sn as the flux.Among them,HfMn_(6)Sn_(6)and ZrMn_(6)Sn_(6)single crystals were grown for the first time.X-ray diffraction measurements reveal that all four samples crystallize in HfFe6Ge6-type hexagonal structure with space group P6/mmm.All samples show metallic behavior from temperature dependence of resistivity measurements,and the dominant carrier is hole,except for GdV6Sn6 which is electron dominated.All samples have magnetic order with different transition temperatures,HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6)and GdV_(6)Sn_(6)are antiferromagnetic with TN of 541 K,466 K and 4 K respectively,while GdMn_(6)Sn_(6)is ferrimagnetic with the critical temperature of about 470 K.This study will enrich the research platform of magnetic kagome materials and help explore the novel quantum phenomena in these interesting materials.The dataset of specific crystal structure parameters for HfMn_(6)Sn_(6)are available in Science Data Bank,with the link.
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921303,2011CBA00100 and 2012CB821404the Strategic Priority Research Program(B) of Chinese Academy of Sciences under Grant Nos XDB07020100and XDB07020200the National Natural Science Foundation of China under Grant No 11174350
文摘We report on the single crystal growth and superconducting properties of PbTaSe2 with the non-centrosymmetric crystal structure. By using the chemicM vapor transport technique, centimeter-size single crystals are success- fully obtained. The measurement of temperature dependence of electricaJ resistivity p（T） in both normal and superconducting states indicates a quasi-two-dimensional electronic state in contrast to that of polycrystalline samples. Specific heat C（T） measurement reveals a bulk superconductivity with Tc ≈ 3.75K and a specific heat jump ratio of 1.42. All these results are in agreement with a moderately electron-phonon coupled, type-g Bardeen-Cooper-Schrieffer superconductor.
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Project supported by the National Natural Science Foundation of China(Grant Nos.10904013 and 11274060)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK2009260 and BK20141329)the Scientific Research Staring Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China
文摘Bi2Te3single crystals were prepared by the solid-state reaction method. The effect of the vacuum on the growth of Bi2Te3 single crystals was studied with varying the oxygen content by controlling the air pressure in the silica tube. High quality Bi2Te3 single crystals have been obtained and there is no influence on the growth by an extremely small amount of oxygen in a high vacuum at 1.0 × 10^-3Pa. As the air pressure is increased at 1.0 × 10^-2Pa, oxygen only mainly impacts on the growth of the surface for the prepared samples. Micron-sized rod-like structure and flower-like clusters are observed on the surface. For the samples prepared at 1.0 × 10^-1Pa, x-ray diffraction data show that the yellow part on the surface is Bi2TeO5, while the Bi2Te3 single crystal is still the major phase as the inside part. More interestingly, various crystal morphologies are observed by scanning electron microscope for Bi2Te3 near the boundary between Bi2Te3 and Bi2TeO5.Possible growth mechanisms for Bi2Te3 with different morphologies are discussed in detail.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB821404)the National Natural Science Foundation of China(Grant Nos.51172166 and 61106005)+1 种基金the National Science Fund for Talent Training in Basic Science of China(Grant No.J1210061)the Doctoral Fund of Ministry of Education of China(Grant No.20110141110007)
文摘High-quality single crystals of A-site ordered perovskite oxides CaCu3Ru4O12 were synthesized by flux method with Cu O serving as a flux. The typical size of these single crystals was around 1 × 1 × 1 mm^3 and the lattice constant was determined to be 7.430 ± 0.0009 ？A by using x-ray single crystal diffraction. The surfaces of the samples were identified to be（100） surface. The high quality of the single crystal samples was confirmed by the rocking curve data which have a full width at half maximum of approximately 0.02 degree. The x-ray photoelectron spectroscopy measurement was performed and the temperature-dependent specific heat, magnetic susceptibility, and electric resistivity were measured along the [100]direction of the single crystals. All these measurements showed that the physical properties of Ca Cu3Ru4O12 single crystals are similar to that of polycrystals. However, the single crystals have a lower Curie susceptibility tail and a smaller residual resistivity than polycrystals, which indicates that the amount of paramagnetic impurities can be controlled by tuning the number of defects in CaCu3Ru4O12 samples.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 51071074, 51172089, and 51171070)the Program for New Century Excellent Talents in University of Ministry of Education of China
文摘We investigate the temperature field variation in the growth region of a diamond crystal in a sealed cell during the whole process of crystal growth by using the temperature gradient method （TGM） at high pressure and high temperature （HPHT）. We employ both the finite element method （FEM） and in situ experiments. Simulation results show that the temperature in the center area of the growth cell continues to decrease during the process of large diamond crystal growth. These results are in good agreement with our experimental data, which demonstrates that the finite element model can successfully predict the temperature field variations in the growth cell. The FEM simulation will be useful to grow larger high-quality diamond crystal by using the TGM. Furthermore, this method will be helpful in designing better cells and improving the growth process of gem-quality diamond crystal.
基金Project supported by the National Natural Science Foundation of China(Grant No.11804305)the Natural Science Foundation of Chongqing,China(Grant No.cstc2019jcyj-msxmX0391)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission,China(Grant No.KJ201901405)the Open Project of State Key Laboratory of Superhard Materials,Jilin University,China(Grant No.201912).
文摘To elucidate the regulation mechanism of catalyst geometry structure to diamond growth,we establish three catalyst modes with different structures.The simulation results show that with the decrease of the protruding height of the catalyst,the low-temperature region gradually moves toward the center of the catalyst,which causes the distribution characteristics of the temperature and convection field in the catalyst to change.The temperature difference in vertical direction of the catalyst decreases gradually and increases in the horizontal direction,while the catalyst convection velocity has the same variation regularity in the corresponding directions.The variation of temperature difference and convection velocity lead the crystal growth rate in different crystal orientations to change,which directly affects the crystal morphology of the synthetic diamond.The simulation results are consistent with the experimental results,which shows the correctness of the theoretical rational analysis.This work is expected to be able to facilitate the understanding of catalyst structure regulation mechanism on diamond morphology and the providing of an important theoretical basis for the controllable growth of special crystal shape diamond under HPHT process.
