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1. Global Minimum Search and Bonding Analysis of Tl ₂ H _x and Tl ₃ H _y (x=0–6; y=0–5) Series

   https://doi.org/10.1002/cphc.202300332  

   Pozdeev, Anton_S; Rublev, Pavel; Boldyrev, Alexander_I; Rao, Yi (July 2023, ChemPhysChem)

   Abstract A remarkable distinction between boron and carbon hydrides lies in their extremely different bonding patterns and chemical reactivity, resulting in diverse areas of application. Particularly, carbon, characterized by classical two‐center – two‐electron bonds, gives rise to organic chemistry. In contrast, boron forms numerous exotic and non‐intuitive compounds collectively called non‐classical structures. It is reasonable to anticipate that other elements of Group 13 exhibit their own unusual bonding patterns; however, our knowledge of the hydride chemistry for other elements in Group 13 is much more limited, especially for the heaviest stable element, thallium. In this work, we performed a conformational analysis of Tl₂H_xand Tl₃H_y(x=0–6, y=0–5) series via Coalescence Kick global minimum search algorithm, DFT, andab initioquantum chemistry methods; we investigated the bonding pattern using the AdNDP algorithm, thermodynamic stability, and stability toward electron detachment. All found global minimum structures are classified as non‐classical structures featuring at least one multi‐center bond. 

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2. Correlating electronic properties with M-site composition in solid solution Ti _y Nb _{2- y} CT _x MXenes

   https://doi.org/10.1088/2053-1583/ac9e68  

   Yang, Yizhou; Han, Meikang; Shuck, Christopher E; Sah, Raj K; Paudel, Jay R; Gray, Alexander X; Gogotsi, Yury; May, Steven J (November 2022, 2D Materials)

   Abstract High electrical conductivity is desired in MXene films for applications such as electromagnetic interference shielding, antennas, and electrodes for electrochemical energy storage and conversion applications. Due to the acid etching-based synthesis method, it is challenging to deconvolute the relative importance that factors such as chemical composition and flake size contribute to resistivity. To understand the intrinsic and extrinsic contributions to the macroscopic electronic transport properties, a systematic study controlling compositional and structural parameters was conducted with eight solid solutions in the Ti y Nb 2− y CT x system. In particular, we investigated the different roles played by metal (M)-site composition, flake size, and d -spacing on macroscopic transport. Hard x-ray photoemission spectroscopy and spectroscopic ellipsometry revealed changes to electronic structure induced by the M-site alloying. Consistent with the spectroscopic results, the low- and room-temperature conductivities and effective carrier mobility are correlated with the Ti content, while the impact of flake size and d -spacing is most prominent in low-temperature transport. The results provide guidance for designing and engineering MXenes with a wide range of conductivities. 

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3. Crystal Growth and Physical Properties of Hybrid CoSn–YCo ₆ Ge ₆ Structure Type Ln _x Co ₃ (Ge _1–y Sn _y ) ₃ (Ln = Y, Gd)

   https://doi.org/10.1021/acs.inorgchem.3c02172  

   Bravo, Moisés; McCandless, Gregory T.; Baumbach, Ryan E.; Wang, Yaojia; Ali, Mazhar N.; Chan, Julia Y. (November 2023, Inorganic Chemistry)
4. Detection of Ultra‐Short KYCDE Peptides Using Si _x N _y Nanopores

   https://doi.org/10.1002/elps.8122  

   Gu, Chaoming; Joty, Kamruzzaman; O'Donohue, Matthew; Thyashan, Navod; Hu, Lifang; Kim, Moon J; Lee, Sangyoup; Kim, Min Jun (July 2025, ELECTROPHORESIS)

   ABSTRACT Detection of ultra‐short peptides is one of the critical steps toward deeper understanding of proteins and the sequencing of amino acids using solid‐state nanopores. The ability of solid‐state nanopores to detect these ultra‐short peptides can help us reveal their hydrodynamic state under different conditions like the concentrations and the external voltage, which may further guide the future development in this field for deeper investigation and possible improvement. In this study, we fabricate Si_xN_ynanopores by CDB with various pore sizes and use them to detect ultra‐short peptides comprised of five different amino acids. The peptide translocation events are extracted under various external voltages. Optimal experimental conditions such as the concentration of electrolytes and analytes, and the range of external voltage are investigated and compared. The statistical results based on volume exclusion analysis indicate that a significant portion of peptides exist in aggregation form. Due to the limitations of Si_xN_ynanopores such as the thickness and the noise, most of the single peptide signals are masked under the baseline noise. In addition, the results show that peptide–pore interactions are dependent upon the diameter of the nanopore. Higher voltage may also influence the degree of peptide aggregations. This study serves to further comprehend the physical and chemical properties of peptides, find possible ways to improve the performance of solid‐state nanopores in the area of protein and peptide detections, and indicate the potential improvements in solid‐state nanopore‐based peptide sequencing. 

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5. Structural phase purification of bulk HfO ₂ :Y through pressure cycling

   https://doi.org/10.1073/pnas.2312571121  

   Musfeldt, J. L.; Singh, Sobhit; Fan, Shiyu; Gu, Yanhong; Xu, Xianghan; Cheong, S.-W.; Liu, Z.; Vanderbilt, David; Rabe, Karin M. (January 2024, Proceedings of the National Academy of Sciences)

   We combine synchrotron-based infrared absorption and Raman scattering spectroscopies with diamond anvil cell techniques and first-principles calculations to explore the properties of hafnia under compression. We find that pressure drives HfO ${}_2$:7%Y from the mixed monoclinic ( $P{2}_1/c$) $+$antipolar orthorhombic ( $\mathit{Pbca}$) phase to pure antipolar orthorhombic ( $\mathit{Pbca}$) phase at approximately 6.3 GPa. This transformation is irreversible, meaning that upon release, the material is kinetically trapped in the $\mathit{Pbca}$metastable state at 300 K. Compression also drives polar orthorhombic ( $Pca{2}_1$) hafnia into the tetragonal ( $P{4}_2/nmc$) phase, although the latter is not metastable upon release. These results are unified by an analysis of the energy landscape. The fact that pressure allows us to stabilize targeted metastable structures with less Y stabilizer is important to preserving the flat phonon band physics of pure HfO ${}_2$. 

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