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1. The proof is in the powder: revealing structural peculiarities in the Yb ₃ Rh ₄ Sn ₁₃ structure type

   https://doi.org/10.1039/C7CE00419B  

   Oswald, Iain W.; Rai, Binod K.; McCandless, Gregory T.; Morosan, Emilia; Chan, Julia Y. (January 2017, CrystEngComm)
2. The role of Co valence in charge transport in the entropy‐stabilized oxide (Mg _0.2 Co _0.2 Ni _0.2 Cu _0.2 Zn _0.2 )O

   https://doi.org/10.1111/jace.18820  

   Jacobson, V.; Huang, J.; Titus, CJ; Smaha, RW; Papac, M.; Lee, SJ; Zakutayev, A.; Brennecka, GL (October 2022, Journal of the American Ceramic Society)

   Abstract Many of the studies on the entropy‐stabilized oxide (Mg_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2)O have been heavily application‐based. Previous works have studied effects of cation stoichiometry on the entropy‐driven reaction to form a single phase, but a fundamental exploration of the effects of anion stoichiometry and/or redox chemistry on electrical properties is lacking. Using near‐edge X‐ray absorption fine structure (NEXAFS) and electrical measurements, we show that oxidizing thin film samples of (Mg_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2)O affects primarily the valence of Co, leaving the other cations in this high‐entropy system unchanged. This oxidation increases electrical conduction in these thin films, which occurs via small polaron hopping mediated by the Co valence shift from 2+ to a mixed 2+/3+ state. In parallel, we show that bulk samples sintered in an oxygen‐rich atmosphere have a lower activation energy for electrical conduction than those equilibrated in a nitrogen (reducing) atmosphere. Combining feasible defect compensation scenarios with electrical impedance measurements and NEXAFS data, we propose a self‐consistent interpretation of Co redox‐mediated small polaron conduction as the dominant method of charge transfer in this system. 

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3. Emergent properties in the natural composite Ni ₂ MnSb _0.5 Al _0.5

   https://doi.org/10.1088/1361-6463/ab7c9f  

   Samanta, Tamalika; Salas, D; Srihari, V; Karaman, I; Bhobe, P A (May 2020, Journal of Physics D: Applied Physics)
4. A quantum dynamical study of the rotation of the dihydrogen ligand in the Fe(H) ₂ (H ₂ )(PEtPh ₂ ) ₃ coordination complex

   https://doi.org/10.1063/1.5026637  

   Gonzalez, Megan E.; Eckert, Juergen; Aquino, Adelia J.; Poirier, Bill (April 2018, The Journal of Chemical Physics)
5. The spontaneous symmetry breaking in Ta ₂ NiSe ₅ is structural in nature

   https://doi.org/10.1073/pnas.2221688120  

   Baldini, Edoardo; Zong, Alfred; Choi, Dongsung; Lee, Changmin; Michael, Marios H.; Windgaetter, Lukas; Mazin, Igor I.; Latini, Simone; Azoury, Doron; Lv, Baiqing; et al (April 2023, Proceedings of the National Academy of Sciences)

   The excitonic insulator is an electronically driven phase of matter that emerges upon the spontaneous formation and Bose condensation of excitons. Detecting this exotic order in candidate materials is a subject of paramount importance, as the size of the excitonic gap in the band structure establishes the potential of this collective state for superfluid energy transport. However, the identification of this phase in real solids is hindered by the coexistence of a structural order parameter with the same symmetry as the excitonic order. Only a few materials are currently believed to host a dominant excitonic phase, Ta 2 NiSe 5 being the most promising. Here, we test this scenario by using an ultrashort laser pulse to quench the broken-symmetry phase of this transition metal chalcogenide. Tracking the dynamics of the material’s electronic and crystal structure after light excitation reveals spectroscopic fingerprints that are compatible only with a primary order parameter of phononic nature. We rationalize our findings through state-of-the-art calculations, confirming that the structural order accounts for most of the gap opening. Our results suggest that the spontaneous symmetry breaking in Ta 2 NiSe 5 is mostly of structural character, hampering the possibility to realize quasi-dissipationless energy transport. 

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