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Endohedral metal-nitride cluster ordering in metallofullerene-NiII(OEP) complexes and crystals : A theoretical study
2019, Dubrovin, Vasilii, Gan, Li-Hua, Büchner, Bernd, Popov, Alexey A., Avdoshenko, Stanislav M.
The ordering of endohedral clusterfullerenes Sc3N@C80 and YSc2N@C80 co-crystallized with Ni(OEP) and isolated complexes with Ni(OEP) have been investigated theoretically. Having used multiple orientations of M3N clusters inside the cages with Fibonacci sampling, we describe the effect of intermolecular interactions on the orientation of the endohedral cluster. © the Owner Societies.
Mg3(Bi,Sb)2 single crystals towards high thermoelectric performance
2020, Pan, Yu, Yao, Mengyu, Hong, Xiaochen, Zhu, Yifan, Fan, Fengren, Imasato, Kazuki, He, Yangkun, Hess, Christian, Fink, Jörg, Yang, Jiong, Büchner, Bernd, Fu, Chenguang, Snyder, G. Jeffrey, Felser, Claudia
The rapid growth of the thermoelectric cooler market makes the development of novel room temperature thermoelectric materials of great importance. Ternary n-type Mg3(Bi,Sb)2 alloys are promising alternatives to the state-of-the-art Bi2(Te,Se)3 alloys but grain boundary resistance is the most important limitation. n-type Mg3(Bi,Sb)2 single crystals with negligible grain boundaries are expected to have particularly high zT but have rarely been realized due to the demanding Mg-rich growth conditions required. Here, we report, for the first time, the thermoelectric properties of n-type Mg3(Bi,Sb)2 alloyed single crystals grown by a one-step Mg-flux method using sealed tantalum tubes. High weighted mobility ∼140 cm2 V−1 s−1 and a high zT of 0.82 at 315 K are achieved in Y-doped Mg3Bi1.25Sb0.75 single crystals. Through both experimental angle-resolved photoemission spectroscopy and theoretical calculations, we denote the origin of the high thermoelectric performance from a point of view of band widening effect and electronegativity, as well as the necessity to form high Bi/Sb ratio ternary Mg3(Bi,Sb)2 alloys. The present work paves the way for further development of Mg3(Bi,Sb)2 for near room temperature thermoelectric applications.