Browsing by Author "Li, Deyu"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Enhanced Electron Correlation and Significantly Suppressed Thermal Conductivity in Dirac Nodal-Line Metal Nanowires by Chemical Doping
    (Wiley, 2023) Coughlin, Amanda L.; Pan, Zhiliang; Hong, Jeonghoon; Zhang, Tongxie; Zhan, Xun; Wu, Wenqian; Xie, Dongyue; Tong, Tian; Ruch, Thomas; Heremans, Jean J.; Bao, Jiming; Fertig, Herbert A.; Wang, Jian; Kim, Jeongwoo; Zhu, Hanyu; Li, Deyu; Zhang, Shixiong
    Enhancing electron correlation in a weakly interacting topological system has great potential to promote correlated topological states of matter with extraordinary quantum properties. Here, the enhancement of electron correlation in a prototypical topological metal, namely iridium dioxide (IrO2), via doping with 3d transition metal vanadium is demonstrated. Single-crystalline vanadium-doped IrO2 nanowires are synthesized through chemical vapor deposition where the nanowire yield and morphology are improved by creating rough surfaces on substrates. Vanadium doping leads to a dramatic decrease in Raman intensity without notable peak broadening, signifying the enhancement of electron correlation. The enhanced electron correlation is further evidenced by transport studies where the electrical resistivity is greatly increased and follows an unusual T$\sqrt T $ dependence on the temperature (T). The lattice thermal conductivity is suppressed by an order of magnitude via doping even at room temperature where phonon-impurity scattering becomes less important. Density functional theory calculations suggest that the remarkable reduction of thermal conductivity arises from the complex phonon dispersion and reduced energy gap between phonon branches, which greatly enhances phase space for phonon–phonon Umklapp scattering. This work demonstrates a unique system combining 3d and 5d transition metals in isostructural materials to enrich the system with various types of interactions.
  • Thumbnail Image
    Item
    Superhydrophobic Array Devices for the Enhanced Formation of 3D Cancer Models
    (American Chemical Society, 2024) Lopez-Cavestany, Maria; Wright, Olivia A.; Reckhorn, Noah T.; Carter, Alexandria T.; Jayawardana, Kalana; Nguyen, Tin; Briggs, Dayrl P.; Koktysh, Dmitry S.; Esteban Linares, Alberto; Li, Deyu; King, Michael R.
    During the metastatic cascade, cancer cells travel through the bloodstream as circulating tumor cells (CTCs) to a secondary site. Clustered CTCs have greater shear stress and treatment resistance, yet their biology remains poorly understood. We therefore engineered a tunable superhydrophobic array device (SHArD). The SHArD-C was applied to culture a clinically relevant model of CTC clusters. Using our device, we cultured a model of cancer cell aggregates of various sizes with immortalized cancer cell lines. These exhibited higher E-cadherin expression and are significantly more capable of surviving high fluid shear stress-related forces compared to single cells and model clusters grown using the control method, helping to explain why clustering may provide a metastatic advantage. Additionally, the SHArD-S, when compared with the AggreWell 800 method, provides a more consistent spheroid-forming device culturing reproducible sizes of spheroids for multiple cancer cell lines. Overall, we designed, fabricated, and validated an easily tunable engineered device which grows physiologically relevant three-dimensional (3D) cancer models containing tens to thousands of cells.