Crystal growth and electronic transport property of ternary Pd-based tellurides

Abstract

Ternary transition-metal chalcogenides are a series of compounds that possess both low-dimensional structures and correlated electrons, and display rich electronic ground states, depending on their different compositions. Among the chalcogen (S, Se, Te), Te has lower electronegativity and heavier atomic mass than S and Se. Thus, transition-metal tellurides take on distinct crystal structures, electronic structures and physical properties. In recent years, we have successively discovered novel superconductors Ta<sub>4</sub>Pd<sub>3</sub>Te<sub>16</sub> and Ta<sub>3</sub>Pd<sub>3</sub>Te<sub>14</sub>, topological Dirac semimetals TaTMTe<sub>5 </sub>(TM = Pd, Pt, Ni),etc., further expanding the investigations of physical properties of the family of tellurides and laying a foundation for exploring their potential applications . The basis of further investigating and exploring the potential applications is the obtaining of the high-quality crystals with large dimensions. In this work, we first introduce the whole procedures of the single-crystal growth in growing the four ternary Pd-based tellurides (Ta<sub>4</sub>Pd<sub>3</sub>Te<sub>16</sub>, Ta<sub>3</sub>Pd<sub>3</sub>Te<sub>14</sub>, TaPdTe<sub>5</sub>, and Ta<sub>2</sub>Pd<sub>3</sub>Te<sub>5</sub>) by employing the self-flux method and chemical vapor transport method, and then give the chemical reaction equations in chemical vapor transport. The superconducting transition width of the Ta<sub>4</sub>Pd<sub>3</sub>Te<sub>16</sub> crystal and Ta<sub>3</sub>Pd<sub>3</sub>Te<sub>14</sub> crystal are as small as 0.57 K and 0.13 K, respectively, and by fitting the temperature-dependent resistivity of the topological insulator Ta<sub>2</sub>Pd<sub>3</sub>Te<sub>5</sub>, the band gap is derived to be 23.37 meV. Finally, we comparatively analyse the crystal-growth processes of the four ternary Pd-based tellurides by employing the flux method, which can provide the inspiration and reference for growing the crystals of other transition-metal tellurides by employing the similar methods.