NbIr 2 B 2 and TaIr 2 B 2 – New Low Symmetry Noncentrosymmetric Superconductors with Strong Spin–Orbit Coupling

Górnicka, Karolina; Gui, Xin; Wiendlocha, Bartlomiej; Nguyen, Loi T.; Xie, Weiwei; Cava, Robert J.; Klimczuk, Tomasz

doi:10.1002/adfm.202007960

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.

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