More Like this

1. H trapping at the metastable cation vacancy in α -Ga ₂ O ₃ and α -Al ₂ O ₃

   https://doi.org/10.1063/5.0094707  

   Venzie, Andrew; Portoff, Amanda; Stavola, Michael; Fowler, W. Beall; Kim, Jihyun; Jeon, Dae-Woo; Park, Ji-Hyeon; Pearton, Stephen J. (May 2022, Applied Physics Letters)

   α-Ga₂O₃has the corundum structure analogous to that of α-Al₂O₃. The bandgap energy of α-Ga₂O₃is 5.3 eV and is greater than that of β-Ga₂O₃, making the α-phase attractive for devices that benefit from its wider bandgap. The O–H and O–D centers produced by the implantation of H⁺and D⁺into α-Ga₂O₃have been studied by infrared spectroscopy and complementary theory. An O–H line at 3269 cm⁻¹is assigned to H complexed with a Ga vacancy (V_Ga), similar to the case of H trapped by an Al vacancy (V_Al) in α-Al₂O₃. The isolated V_Gaand V_Aldefects in α-Ga₂O₃and α-Al₂O₃are found by theory to have a “shifted” vacancy-interstitial-vacancy equilibrium configuration, similar to V_Gain β-Ga₂O₃, which also has shifted structures. However, the addition of H causes the complex with H trapped at an unshifted vacancy to have the lowest energy in both α-Ga₂O₃and α-Al₂O₃. 

   more » « less
2. Boron‐Made N ₂ : Realization of a B≡B Triple Bond in the B ₂ Al ₃ ⁻ Cluster

   https://doi.org/10.1002/chem.202001159  

   Fedik, Nikita; Mu, Chaonan; Popov, Ivan A.; Wang, Wei; Wang, Jie; Wang, Haopeng; Bowen, Kit H.; Boldyrev, Alexander I.; Zhang, Xinxing (June 2020, Chemistry – A European Journal)
3. Final results for the neutron β -asymmetry parameter A ₀ from the UCNA experiment

   https://doi.org/10.1051/epjconf/201921904004  

   Plaster, B.; Adamek, E.; Allgeier, B.; Anaya, J.; Back, H.O.; Bagdasarova, Y.; Berguno, D.B.; Blatnik, M.; Boissevain, J.G.; Bowles, T.J.; et al (January 2019, EPJ Web of Conferences)

   The UCNA experiment was designed to measure the neutron β-asymmetry parameter A 0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A 0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A 0 . 

   more » « less
4. Rupture Directivity of the 2021 M _W 6.0 Yangbi, Yunnan Earthquake

   https://doi.org/10.1029/2022JB024321  

   Gong, Wenzheng; Ye, Lingling; Qiu, Yuxin; Lay, Thorne; Kanamori, Hiroo (September 2022, Journal of Geophysical Research: Solid Earth)

   Abstract The 2021M_W6.0 Yangbi, Yunnan strike‐slip earthquake occurred on an unmapped crustal fault near the Weixi‐Qiaoho‐Weishan Fault along the southeast margin of the Tibetan Plateau. Using near‐source broadband seismic data from ChinArray, we investigate the spatial and temporal rupture evolution of the mainshock using apparent moment‐rate functions (AMRFs) determined by the empirical Green's function (EGF) method. Assuming a 1D line source on the fault plane, the rupture propagated unilaterally southeastward (∼144°) over a rupture length of ∼8.0 km with an estimated rupture speed of 2.1 km/s to 2.4 km/s. A 2D coseismic slip distribution for an assumed maximum rupture propagation speed of 2.2 km/s indicates that the rupture propagated to the southeast ∼8.0 km along strike and ∼5.0 km downdip with a peak slip of ∼2.1 m before stopping near the largest foreshock, where three bifurcating subfaults intersect. Using the AMRFs, the radiated energy of the mainshock is estimated as ∼. The relatively low moment scaled radiated energyof 1.5 × 10⁻⁵and intense foreshock and aftershock activity might indicate reactivation of an immature fault. The earthquake sequence is mainly distributed along a northwest‐southeast trend, and aftershocks and foreshocks are distributed near the periphery of the mainshock large‐slip area, suggesting that the stress in the mainshock slip zone is significantly reduced to below the level for more than a few overlapping aftershock to occur. 

   more » « less
5. Thermal Conductivity of β-Phase Ga ₂ O ₃ and (Al _x Ga _{1– x} ) ₂ O ₃ Heteroepitaxial Thin Films

   https://doi.org/10.1021/acsami.1c08506  

   Song, Yiwen; Ranga, Praneeth; Zhang, Yingying; Feng, Zixuan; Huang, Hsien-Lien; Santia, Marco D.; Badescu, Stefan C.; Gonzalez-Valle, C. Ulises; Perez, Carlos; Ferri, Kevin; et al (August 2021, ACS Applied Materials & Interfaces)