Temperature-dependent transport properties of a FeTe compound

Abstract

Temperature-dependent transport properties of a FeTe parent compound have been investigated by measurements of electrical resistivity ρ(T), thermal conductivity κ(T) and Seebeck coefficient S(T). The sample was synthesized using a standard solid state reaction route via vacuum encapsulation and characterized by X-ray diffraction spectroscopy, which indicated a tetragonal phase with the space group P4/nmm. The resistivity measurement data of the parent FeTe compound do not exhibit superconductivity however, it shows an anomaly in the temperature-dependent resistivity at around 67 K, which corresponds to structural phase transition in the vicinity of a magnetic phase transition. In the low temperature regime, Seebeck coefficient, S(T), exhibited an anomalous dip feature and negative throughout the temperature range, indicating an electron-like, single band charge carrier mechanism. We have also estimated the power factor and thermoelectric figure of merit ZT, which is found to be significantly smaller than other compositions of iron chalcogenides.

Rational Design of 3d Transition-Metal Compounds for Thermoelectric Properties by Using Periodic Trends in Electron-Correlation Modulation

“…Figure shows the values of thermoelectric power factor (PF) and figure of merit ( ZT ) on a Δ− U diagram featuring 30 various types of transition-metal compounds (Table S3). ,− Figure also shows values of Δ norm (= Δ – Δ B ) and U norm (= U – U B ) that were normalized using Δ B and U B to facilitate direct comparisons between each compound group. U B values of 13 and 11 eV were assumed for the calculations of phosphides, arsenides, and halides, respectively.…”

Anomalous Thermoelectric Transport Properties of Fe‐Rich Magnetic FeTe

“…Similar to the magnetic and structural properties, the thermoelectric transport properties of FeTe exhibit anomalies at ≈70 K, also reported in previous literature. [ 18–22 ] The temperature‐dependent thermoelectric transport properties, including the electrical conductivity ( σ ), thermal conductivity ( κ ), and thermopower ( α ) at 0 and 12 T fields are measured and the thermoelectric‐figure‐of‐merit () are calculated from experimentally measured properties, shown in Figure . The electrical conductivity shows a decremental trend with the increase in the temperature with a discontinuity at the magnetostructural phase transition temperature.…”

“…[4,16,17] Due to the existence of a magnetic state along with the probable superconducting quantum state, FeTe has been studied as a thermoelectric material with little understanding of the anomalies seen in transport properties. [18][19][20][21][22] The anomalies can be attributed to both structural and magnetic phase transitions happening at the same temperature. [4,16,17] To understand the individual contributions from the structural change and magnetic phase transition, an inclusive study of the magnetic properties, electrical properties, and heat capacity along with other transport properties can shed light on the underlying principle of the anomaly in thermoelectric properties.…”