Thermoelectric Properties of Variants of Cu₄Mn₂Te₄ with Spinel-Related Structure

Abstract

Thermoelectric properties of CuMnTe, which is antiferromagnetic with a Néel temperature T = 50 K and crystallizes in a spinel-related structure, have been investigated comprehensively here. The phase transition occurring at temperatures 463 and 723 K is studied by high-temperature X-ray diffraction (XRD) and differential scanning calorimetry (DSC), and its effect on thermoelectric properties is examined. Hypothetically CuMnTe is semiconducting according to the formula (Cu)(Mn)(Te), while experimentally it shows p-type metallic conduction behavior, exhibiting electrical conductivity σ = 2500 Ω cm and Seebeck coefficient α = 20 μV K at 325 K. Herein, we show that the carrier concentration and thus the thermoelectric transport properties could be further optimized through adding electron donors such as excess Mn. Discussions are made on the physical parameters contributing to the low thermal conductivity, including Debye temperature, speed of sound, and the Grüneisen parameter. As a result of simultaneously boosted power factor and reduced thermal conductivity, a moderately high zT = 0.65 at 680 K is obtained in an excess Mn\In co-added sample, amounting to 5 times that of the pristine CuMnTe. This value ( zT = 0.65) is the best result ever reported for spinel and spinel-related chalcogenides.

Tailoring the thermoelectric and structural properties of Cu–Sn based thiospinel compounds [CuM1+xSn1−xS4 (M = Ti, V, Cr, Co)]

“…[29][30][31][32] Incidentally, some tellurides with spinel-related structures have also been found lately with relatively high thermoelectric performance. 33,34 Although some attractive themoelectric properties have been reported for thiospinel compounds in the family of the general composition CuM2S4, such as CuCo2S4, CuTi2S4, CuCr2S4 and their derivatives (where Co, Ti, Cr are partially substituted for each other), [29][30][31][32]35 not much information is available on the thermoelectric properties of Sn-based thiospinel compounds and their derivatives.…”

Accelerated Discovery of Advanced Thermoelectric Materials via Transfer Learning

“…Beyond the initial dataset (i.e., for the testing set), we have employed the above TL model to predict the ZT of eight randomly selected systems from literatures. [53][54][55][56][57][58][59] There are 19 p-and 27 n-type entries by considering the temperature dependence, which are summarized in Part 5 of the Supporting Information. As shown in Figure 4 (red points), our results exhibit good agreements with those measured experimentally, which is demonstrated by high PCCs of 95% and 94% for the p-and n-type systems, respectively.…”

Rational Design of Spinel-Type Cu4Mn2Te4/TMTe (TM = Co, Ni) Composites with Synergistically Manipulated Electrical and Thermal Transport Properties

“…Interpreting (4 – y )Cu + yTM + 2Mn + 4Te → (4 – y )/4Cu 4 Mn 8/(2–y) Te 4 + y TMTe (TM = Co, Ni), the formation of the TMTe precipitates is imperative in terms of optimizing the carrier concentration, as it results in a slightly higher content of Mn in the matrix and a consequent decrease of hole concentration toward the optimal region. − …”

“…For example, Guo et al found that its low κ is strongly related with its high Gruneisen parameter, low Debye temperature, and low speed of sound. 40 Chen et al, for the first time, studied the synergistic effect of Te deficiency and Cldoping in ternary Cu 4 Mn 2 Te 4 and achieved a 100% enhancement in zT (=0.4) at 700 K. 41 Li et al systematically assessed Cu 4 Mn 2 Te 4 with different carrier concentrations and demonstrated that zT = 1.0 is achievable when the carrier concentration is tuned to ∼3−4 × 10 20 cm −3 utilizing the canonical single parabolic model. 42 They also revealed the underlying physics of Cu 4 Mn 2 Te 4 , such as deformation potential and density of effective mass.…”

“…Early work documented the crystal structure, electrical properties, and magnetic properties of Cu 4 Mn 2 Te 4 . , Recently, this has attracted increasing attention and research efforts as an attractive thermoelectric system. For example, Guo et al found that its low κ is strongly related with its high Grüneisen parameter, low Debye temperature, and low speed of sound . Chen et al, for the first time, studied the synergistic effect of Te deficiency and Cl-doping in ternary Cu 4 Mn 2 Te 4 and achieved a 100% enhancement in zT (=0.4) at 700 K .…”