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1. a -axis YBa2Cu3O7− x /PrBa2Cu3O7− x /YBa2Cu3O7− x trilayers with subnanometer rms roughness

   https://doi.org/10.1063/5.0034648  

   Suyolcu, Y_Eren; Sun, Jiaxin; Goodge, Berit_H; Park, Jisung; Schubert, Jürgen; Kourkoutis, Lena_F; Schlom, Darrell_G (February 2021, APL Materials)

   We demonstrate a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The trilayers are synthesized by ozone-assisted molecular-beam epitaxy. The thickness of the PrBa2Cu3O7−x layer is held constant at 8 nm, and the thickness of the YBa2Cu3O7−x layers is varied from 24 nm to 100 nm. X-ray diffraction measurements show all trilayers to have >97% a-axis content. The rms roughness of the thinnest trilayer is <0.7 nm, and this roughness increases with the thickness of the YBa2Cu3O7−x layers. The thickness of the YBa2Cu3O7−x layers also affects the transport properties: while all samples exhibit an onset of the superconducting transition at and above 85 K, the thinner samples show wider transition widths, ΔTc. High-resolution scanning transmission electron microscopy reveals coherent and chemically sharp interfaces and that growth begins with a cubic (Y,Ba)CuO3−x perovskite phase that transforms into a-axis oriented YBa2Cu3O7−x as the substrate temperature is ramped up. 

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2. Transport Properties of GdTe _{1.8– x} As _x ( x = 0, 0.04)

   https://doi.org/10.1002/ejic.202000195  

   Poddig, Hagen; Hobbis, Dean; Alzahrani, Noha; Doert, Thomas; Nolas, George S. (June 2020, European Journal of Inorganic Chemistry)
3. Thermoelectric properties of YbZn _11−x Al _x

   https://doi.org/10.1039/D4MA00626G  

   Li, Shuai; Quddus, Ruhul; Das, Sree Sourav; Wang, Haobo; Floro, Jerrold A; Zebarjadi, Mona (October 2024, Materials Advances)

   The first investigation on the properties of intermetallic YbZn₁₁for active cooling: an unconventional thermoelectric application. 

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4. Phase stability and mechanical properties of Mo _{1- x} N _x with 0 ≤ x ≤ 1

   https://doi.org/10.1063/1.4998686  

   Balasubramanian, Karthik; Huang, Liping; Gall, Daniel (November 2017, Journal of Applied Physics)
5. From prediction to experimental realization of ferroelectric wurtzite Al1− x Gd x N alloys

   https://doi.org/10.1063/5.0251168  

   Lee, Cheng-Wei; Smaha, Rebecca_W; Brennecka, Geoff_L; Haegel, Nancy_M; Gorai, Prashun; Yazawa, Keisuke (February 2025, APL Materials)

   AlN-based alloys find widespread application in high-power microelectronics, optoelectronics, and electromechanics. The realization of ferroelectricity in wurtzite AlN-based heterostructural alloys has opened up the possibility of directly integrating ferroelectrics with conventional microelectronics based on tetrahedral semiconductors, such as Si, SiC, and III–Vs, enabling compute-in-memory architectures, high-density data storage, and more. The discovery of AlN-based wurtzite ferroelectrics has been driven to date by chemical intuition and empirical explorations. Here, we demonstrate the computationally-guided discovery and experimental demonstration of new ferroelectric wurtzite Al1−xGdxN alloys. First-principles calculations indicate that the minimum energy pathway for switching changes from a collective to an individual switching process with a lower overall energy barrier, at a rare-earth fraction x with x > 0.10–0.15. Experimentally, ferroelectric switching is observed at room temperature in Al1−xGdxN films with x > 0.12, which strongly supports the switching mechanisms in wurtzite ferroelectrics proposed previously [Lee et al., Sci. Adv. 10, eadl0848 (2024)]. This is also the first demonstration of ferroelectricity in an AlN-based alloy with a magnetic rare-earth element, which could pave the way for additional functionalities such as multiferroicity and opto-ferroelectricity in this exciting class of AlN-based materials. 

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