曾皙

The high valence vacancy Sb can be stabilized by Al atom, which causes intensified chemical bonds and lowers the formation energy of Sb vacancy. These high valance vacancies can efficiently provide multiple carriers in Cu₃SbS₄ and realize high doping efficiency. As a result, both superior thermoelectric performance and high power factor are attained in Cu₃SbS₄, which is among the best in low-toxic thermoelectric sulfides.

Abstract

Sulfides are well investigated as thermoelectric materials but their performance is typically limited by low electrical conductivity. High electrical performance in Cu₃SbS₄ is reported by creating high valence vacancies, which efficiently provides multiple carriers. It is revealed from the perspective of a chemical bond by calculations that Al can serve as vacancy stabilizer as its entry into the lattice forms intensified bonds with neighboring atoms and lowers the vacancy formation energy. As a result, the average power factor of Cu₃SbS₄ with 9 wt% CuAlS₂ reaches 16.1 µW cm⁻¹ K⁻². Finally, by further addition of AgAlS₂, a peak zT of 1.3 and an average zT of 0.77 are obtained due to the reduced thermal conductivity. The attained average power factor and average zT are superior to other low-toxic thermoelectric sulfides. The findings shed light on the new strategy for creating favorable vacancies to realize high-efficiency doping in thermoelectric materials.

Nature Energy, Published online: 23 September 2021; doi:10.1038/s41560-021-00892-9

Understanding support for or opposition to energy developments — and how it varies with proximity — is important for effective planning. A new study using public comments on a regulatory review casts further light on the geography of discourse and how it might shape action on siting energy technology.

Author(s): K.-W. Chen, G. Chappell, S. Zhang, W. Lan, T. Besara, K. Huang, D. Graf, L. Balicas, A. P. Reyes, and R. E. Baumbach

Results are reported for single crystals of the PbFCl-type layered compound ZrP1.27Se0.73 that were produced using the iodine vapor transport method. Electrical transport, magnetization, and heat capacity measurements reveal disordered metallic behavior and the occurrence of bulk superconductivity, ...

[Phys. Rev. B 102, 144522] Published Thu Oct 22, 2020

The two intermetallic compounds NbIr₂B₂ and TaIr₂B₂, which display a previously unreported noncentrosymmetric crystal structure, are superconductors with T _c  = 7.2 and 5.1 K, respectively. Strong spin–orbit coupling splits their Fermi surfaces. The upper magnetic critical fields significantly exceed the Pauli limits, suggesting that the superconductivity may be unconventional.

Abstract

Superconductivity was first observed more than a century ago, but the search for new superconducting materials remains a challenge. The Cooper pairs in superconductors are ideal embodiments of quantum entanglement. Thus, novel superconductors can be critical for both learning about electronic systems in condensed matter and for possible application in future quantum technologies. Here two previously unreported materials, NbIr₂B₂ and TaIr₂B₂, are presented with superconducting transitions at 7.2 and 5.2 K, respectively. They display a unique noncentrosymmetric crystal structure, and for both compounds the magnetic field that destroys the superconductivity at 0 K exceeds one of the fundamental characteristics of conventional superconductors (the “Pauli limit”), suggesting that the superconductivity may be unconventional. Supporting this experimentally based deduction, first‐principle calculations show a spin‐split Fermi surface due to the presence of strong spin–orbit coupling. These materials may thus provide an excellent platform for the study of unconventional superconductivity in intermetallic compounds.