Single Crystal Growth And Physical Properties Of Ta-Pd-Te Ternary Tellurides

Ternary Pd-based tellurides are a series of compounds that possess both low-dimensional structures and correlated electrons,and display rich electronic ground states according to its different compositions.So far,four ternary Pd-based tellurides have been reported,which are superconductors Ta₄Pd₃Te₁₆ and Ta₃Pd₃Te₁₄,Dirac semi metal Ta Pd Te₅,and second-order topological insulator Ta₂Pd₃Te₅.Above materials are layered transition metal tellurides with quasi-one-dimensional chains.Studying this series and exploring tellurides formed by other transition metal will also be interesting.In this paper,we mainly discussed the single crystal growth and physical properties of Ta-Pd-Te ternary telluride crystals,and the main conclusions are as following:（1）The whole procedures of the single-crystal growth in growing the four ternary Pd-based tellurides(Ta₄Pd₃Te₁₆,Ta₃Pd₃Te_14,Ta Pd Te₅,and Ta₂Pd₃Te₅)by employing the self-flux method and chemical vapor transport method,and then gives the chemical reaction equations in chemical vapor transport.The superconducting transition widths of the Ta₄Pd₃Te₁₆ and Ta₃Pd₃Te₁₄ crystals are as small as 0.61K and 0.13K,and by fitting the temperature-dependent resistivity of the topological insulator Ta₂Pd₃Te₅,the band gap is derived to be 23.37 me V.Then,we comparatively analyse the crystal-growth processes of the four ternary Pd-based tellurides by employing the flux method,which can provide inspiration and reference for growing the crystals of other transition-metal tellurides by employing the similar methods.（2）Single crystal of Ta₂Pd₃Te₅,polycrystal of Ta₂Pd₃Te₅,and polycrystal of 5%Te vacancy doped Ta₂Pd₃Te_5（1-x）（x=0.05）were synthesized.The Ta₂Pd₃Te₅ polycrystals displays zero resistance state at 3.63K,but does not exhibit perfect diamagnetism;The polycrystalline sample of Ta₂Pd₃Te_5（1-x）（x=0.05）displays superconducting transition at3.60K,and the ZFC diamagnetic volume fraction is 99.7%.By measuring the specific heat near the superconducting transition temperature,no specific heat jump was observed,indicating that this superconductivity is not bulk properties,and may be caused by impurity.（3）Due to the fact that elements of the same period or group often have similar properties,therefore,it is worthwhile to attempted to explore new Ta-Rh-Te ternary tellurides and Ta-Re-Te ternary tellurides composed of elements Rh and Re adjacent to Pd.We conducted preliminary exploration and measured the electrical transport properties of the products.