Single crystal growth and transport properties of narrow-bandgap semiconductor RhP_(2)

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.

Single crystal growth and characterization of 166-type magnetic kagome metals

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.

Single crystal growth and electronic structure of Rh-doped Sr_(3)Ir_(2)O_(7)

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.

Precipitates identification in R_2PdSi_3(R= Pr,Tb and Gd) single crystal growth

Floating zone method with optical radiation heating was applied to growing a class of R2PdSi3（R=Pr,Tb and Gd） single crystals due to its containerless melting and high stability of the floating zone.One serious problem during the single crystal growth,precipitates of secondary phases,was discussed from the following four parts：precipitates from the raw materials and preparation process,precipitates formed during the growing process,precipitates in the melts and precipitates in the grown crystals.Annealing treatment and composition shift can effectively reduce the precipitates which are not formed during the crystallization but precipitated on post-solidification cooling from the as-grown crystal matrix because of the retrograde solubility of Si.

Single Crystal Growth and Physical Property Characterization of Non-centrosymmetric Superconductor PbTaSe_2

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.

Synthesis,Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-（3-amino-[1,2,4]triazol-1-yl）-3,3-dimethyl-butan-2-one（3） was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one（1） and ~1H-[1,2,4]triazol-3-ylamine（2） with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227（8）, b = 27.924（4）, c = 6.2282（7） ？, β = 101.892（11）°, V = 973.9（2） ？~3, Z = 4, T = 180.00（10） K, μ（MoKα） = 0.087 mm^（-1）, Dc = 1.243 g/cm^3, 3832 reflections measured（3.648≤θ≤26.022°）, 1916 unique reflections（Rint = 0.0359, Rsigma = 0.0572） used in all calculations. The final R = 0.0557（I 〉 2σ（I）） and w R = 0.1276（all data）. Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L（50 ppm） in soybeen（He Feng-50）. Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.

Synthesis, Single-crystal Structure, and Optical and Magnetic Properties of CaEr_2S_4

Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a=12.845（4）, b=3.862（4）, c=13.001（2）（A）, V=645.0（7）（A）3,Z=4, F（000）=880,μ（MoKα）=27.794 mm^-1, the final R=0.0528 and wR=0.0562 for 1070observed reflections with I 〉 3σ（I）. The CaEr2S4 structure forms a three-dimensional framework that consists of interconnected tetra-octahedral Er4S18 fragments. Ca^2＋cations, in a monocapped trigonal prism geometry, are stuffed in two parallel rows into the one-dimensional channels along the b direction. CaEr2S4 is an infrared-transparent semiconductor with a band gap of 1.81 eV. Magnetic susceptibility measurements over 6～300 K indicate a Curie-Weiss paramagnetic behavior for the phase, with an effective magnetic moment of 9.64（1） μB per Er^3＋ ion.

MORPHOLOGY OF(Mn,Fe)S SINGLE CRYSTAL GROWTH IN CAST STEEL

The step pattern of single crystal growth and the morphology at equilibrium state of(Mn, Fe)S on the wall of micro-voids in ZG25 cast steel have been observed using scanning electron microscope.The face-centred cubic(Mn,Fe)S single crystal at equilibrium state is shown to be tetrakaidecahedron consisted of eight{111}planes and six{100}planes,and is a typical example of the O_h—m3m cubic crystal system.

Novel Synthesis, Crystal Structure, and Plant-growth Regulation Activity of(1S,4R)-4,7,7-Trimethyl-6-oxabicyclo[3.2.1]octane-1,4-diol

The title compound,（1S,4R）-4,7,7-trimethyl-6-oxabicyclo [3.2.1] octane-1,4-diol（C（10）H（18）O3）, has been synthesized from terpinolene via one-step catalytic synthetic method and structurally characterized by means of HRMS, IR, 1H-NMR, （13）C-NMR and single-crystal X-ray diffraction. The compound crystallizes in trigonal, space group R-3, with a = 27.892（9）, b = 27.892（9）, c = 6.720（2） A, γ = 120°, Z = 18, V = 4527（3） A3, Dc = 1.230 g/cm3, Mr = 186.24, λ（Mo Kα） = 0.71073？, μ = 0.09 mm（-1）, F（000） = 1836, the final R = 0.051 and wR = 0.161. The title compound molecule contained a 6-oxabicyclo[3.2.1]octane skeleton and two hydroxyl groups, which were connected through intermolecular O–H…O hydrogen bonds to generate a two-dimensional network. Especially, the preliminary bioassay showed that the title compound can promote the root growth and shoot elongation of rape（Brassica campestris） at low concentration（0.62570 mmol·L^-1） and inhibit them at high concentration（〉 70 mmol·L^-1）.

Bulk single crystal growth of SiGe by PMCZ method

A new type of magnetic device was used to replace the conventionalelectro-magnetic field for CZSi (doped with Ge) growth. The device was composed of three permanentmagnetic rings and called PMCZ device. The lines of magnetic force are horizontally distributed atradial 360℃. Using the ring permanent magnetic field, thermal convection in melt and centrifugalpumping flows due to crystal rotation could be strongly suppressed so that the fluctuations oftemperature and micro-growth rate at solid/liquid interface could be restrained effectively. In thePMCZ condition, the growing environment of SiGe bulk single crystal was similar to the crystalgrowth in space under the condition of micro-gravity. The motion of impurities (Ge, oxygen, etc.)had been controlled by diffusion near the solid/liquid interface. Oxygen concentration became lowerand the distribution of composition became more homogeneous along longitudinal direction and acrossa radial section in the grown SiGe crystal. The mechanism of PMCZ superior to MCZ was alsodiscussed.

Machine Learning to Instruct Single Crystal Growth by Flux Method

Growth of high-quality single crystals is of great significance for research of condensed matter physics. The exploration of suitable growing conditions for single crystals is expensive and time-consuming, especially for ternary compounds because of the lack of ternary phase diagram. Here we use machine learning(ML) trained on our experimental data to predict and instruct the growth. Four kinds of ML methods, including support vector machine(SVM), decision tree, random forest and gradient boosting decision tree, are adopted. The SVM method is relatively stable and works well, with an accuracy of 81% in predicting experimental results. By comparison,the accuracy of laboratory reaches 36%. The decision tree model is also used to reveal which features will take critical roles in growing processes.

Single crystal growth, structural and transport properties of bad metal RhSb2

We have successfully grown an arsenopyrite marcasite type RhSb2 single crystal, and systematically investigated its crystal structure, electrical transport, magnetic susceptibility, heat capacity, and thermodynamic properties. We found that the temperature-dependent resistivity exhibits a bad metal behavior with a board peak around 200 K. The magnetic susceptibility of RhSb2 shows diamagnetism from 300 K to 2 K. The low-temperature specific heat shows a metallic behavior with a quite small electronic specific-heat coefficient. No phase transition is observed in both specific heat and magnetic susceptibility data. The Hall resistivity measurements show that the conduction carriers are dominated by electrons with ne = 8.62 × 10^(18) cm^(-3) at 2 K, and the electron carrier density increases rapidly above 200 K without change sign. Combining with ab-initio band structure calculations, we showed that the unusual peak around 200 K in resistivity is related to the distinct electronic structure of RhSb_2. In addition, a large thermopower S(T) about -140 μV/K is observed around 200 K, which might be useful for future thermoelectric applications.

Single crystal growth and characterizations of iron arsenide superconductor BaFe_(2-x)Ni_xAs_2(0.0≤x≤0.12)

A series of big single crystals of BaFeFe2-xNixAs2 have been prepared by the FeAs self-flux method, with nominal nickel doping x = 0--0.12. The dimensions of the cleaved crystals are over 10~mm along ab plane and ～ 2~mm in maximum along the c direction. The measurements of x-ray diffraction, electrical resistance and magnetic property are carried out on the crystals. For the undoped parent compound BaFe2As2, both resistance and magnetization data display an anomaly associated with spin density wave and/or structural phase transition, with the transition temperatures at ～ 138~K. For Ni-doped BaFe2-xNixAs2 crystals, the superconducting critical temperature Tc ranges from 4.3~K for x=0.06 sample to 20~K for the optimally doped x=0.10 crystal.

Single Crystal Growth and Magnetoresistivity of Topological Semimetal CoSi

We report single crystal growth of CoSi, which has recently been recognized as a new type of topological semimetal hosting fourfold and sixfold degenerate nodes. The Shubnikov–de Haas quantum oscillation(QO) is observed on our crystals. There are two frequencies originating from almost isotropic bulk electron Fermi surfaces, in accordance with band structure calculations. The effective mass, scattering rate, and QO phase difference of the two frequencies are extracted and discussed.

Synthesis, Growth, Crystal Structure and Characterization of the o-Toluidinium Picrate

A new organic charge transfer molecular complex salt of o-toluidinium picrate (OTP) was synthesised and the single crystals were grown by the slow solvent evaporation solution growth technique using methanol as a solvent at room temperature. Formation of the new crystal has been confirmed by single crystal X-ray diffraction (XRD) and NMR spectroscopic techniques. The crystal structure determined by single crystal X-ray diffraction indicates that both the cation and the anion are interlinked to each other by three types of intermolecular hydrogen bonds, namely N(4)-H(4A)···O(7), N(4)-H(4B)···O(5) and N(4)-H(4C)···O(7). The title compound (OTP) crystallizes in monoclinic crystal system with the centrosymmetric space group P21/c. Fourier transform infrared (FT IR) spectral analysis was used to confirm the presence of various functional groups in the grown crystal. The optical properties were analyzed by the UV-Vis-NIR and fluorescence emission studies.

Synthesis,Single-crystal Structure,and Computational Studies of a Yavapaiite Structure Compound:Pb(Sb0.5Fe0.5)(PO4)2

The single crystals and powder of a Yavapaiite Structure phosphate,namely,PbSb0.5Fe0.5（PO4）2,were synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction.The title compound crystallizes in the monoclinic system,space group C2/c（No.15） with a = 16.716（4）,b = 5.186（7）,c = 8.130（2）A,β = 114.93（6）°,Z = 4,R（I 〉 2s（I）） = 0.0430,R indices（all data） = 0.0460,and T = 293（2） K.The title compound belongs to the Yavapaiite Structure A^（Ⅱ）M^（Ⅳ）（PO4）2 compounds,and the Sb1 atom and Fe1 atoms occupy the same site（M） and their occupancy factors are refined to be 0.5 and 0.5 having a sum occupancy factor of 1.0.Its structure consists of [M（PO）4]n^2n- layers running parallel to the（b,c） plane built up of cornerconnected MO6 octahedra and PO4 tetrahedra.Additionally,the calculations of energy band structure,and density of states have been performed with the density functional theory method.The studies of computational calculation and UV experimental results show that the new compound is an indirect band-gap insulator.

Syntheses, Crystal Structures and DNA-binding Properties of Zn(Ⅱ), Ni(Ⅱ) and Co(Ⅱ) Compounds Containing Thiazole Derivatives

Zn(Ⅱ), Ni(Ⅱ) and Co(Ⅱ) compounds(1～3) based on 2-(2-pyridyl)benzothiazole(bpt) and terephthalic acid(PTA) were synthesized. The crystal structures of [Zn(bpt)(PTA)2](1), [Ni(bpt)(PTA)2](2), and [Co(bpt)(PTA)2](3) have been determined by single-crystal X-ray diffraction analysis, which shows that all the three complexes belong to monoclinic system with space group P21/c. Time-dependent density functional theory(TD-DFT) calculation is performed on a reference structure of compound 3. The excited electrons mainly localized at the π* of ligand 2-(2-pyridyl)benzothiazole, which will be convenient for them to bind with the DNA reacting sites. Fluorescence spectroscopy, ultraviolet(UV) spectroscopy and viscosity were used to characterize the interaction of the compounds with Calf thymus DNA(CT-DNA). The results indicate that compounds 1～3 bind to CT-DNA and have a strong interaction with DNA. The compounds can probably bind to CT-DNA via a non-intercalative mode as concluded by studying the viscosity of a DNA solution in the presence of the compounds. This combination can effectively break DNA, which speculates that these three compounds may interact with the cancer cell DNA in this binding mode, thereby damaging the cancer cells.

Crystal Structure of a Mn(Ⅱ) Coordination Polymer:[Mn(TP)(TBZH)_(2n)(TBZH=Thiabendazole,TP=Terephthalic Acid)

The structure of a manganese（Ⅱ） polymer,[Mn（TP）（TBZH）]2n 1（TBZH=thiabendazole,TP=terephthalic acid）,has been determined by X-ray crystallography and characterized by elemental analysis,IR spectrum and thermogravimetric analysis.It crystallizes in the orthorhombic system,space group Pbcn with a=12.7813（12）,b=10.7544（10）,c=20.1270（19）A,V=2766.6（4）A^3,Z=8,C14H9Mn0.50N3O2S,Mr=310.77,Dc=1.492g/cm^3,F（000）=1268,μ=0.674 mm^-1 and S=1.064.The 1-D chain architecture of 1 is constructed from terephthalic acid and manganese atoms.Hydrogen bonds and aryl ring π-π stacking interactions in 1 contribute to form a 3-D supramo-lecular structure.

Synthesis and Crystal Structure of(Z)-5-fluoro-3-(phenyl((5-(pyridin-3-ylmethyl)thiophen-2-yl)amino)methylene)Indolin-2-one

The crystal structure of the title compound （Z）-5-fluoro-3-（phenyl（（5-（pyridin-3- ylmethyl）thiophen-2-yl）amino）methylene） indolin-2-one （C25H18FN3OS, Mr = 427.50） has been prepared and determined by single-crystal X-ray diffraction. The crystal is of orthorhombic, space group P212121 with a = 5.931（1）, b = 12.413（1）, c = 28.102（2） A, V= 2090.4（3） A3, Z = 4, Dc = 1.358 g/cm3, F（000） = 888, μ= 0.186 mm-1, MoKa radiation （2 = 0.71073）, R = 0.041 and wR = 0.105 for 4567 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the indole and thiophene rings are not coplanar with a dihedral angle of 46.26（5）°. Intramolecular and intermolecular N-H＇..O hydrogen bonds together with C-H...π interations can be observed in the lattice.

A New Pleuromutilin Derivative: Synthesis,Crystal Structure and Antibacterial Evaluation

A new pleuromutilin derivative, 14-O-[（4,6-diaminopyrimidine-2-yl） thioacetate] mutilin, was synthesized and structurally characterized by IR, NMR spectra and single-crystal X-ray diffraction. This compound contains a 5-6-8 tricyclic carbon skeleton and a pyrimidine ring. Its crystal is of orthorhombic system, space group P21 with a = 10.0237（6）, b = 12.6087（7）, c = 10.3749（8） A, fl = 101.48（1）°, V = 1284.99（14） A3, Z = 2, F（000） = 540, Oc（Mg/m3） = 1.299, # = 0.165 mm1, R = 0.0649 and wR = 0.0797. The in vitro antibacterial activity study using Oxford cup assay showed this compound displayed more potent activity than pleuromutilin and similar antibacterial activity to that oftiamulin.