Improved Thermoelectric by Asymmetric Resonant-Tunneling Magnetic Tunnel Junctions Incorporating β-Ga 2 O 3 Semiconductor and Dissimilar Ferromagnets

This study investigates the thermoelectric (TE) performance of asymmetric resonant-tunneling magnetic tunnel junctions (A-RT-MTJs) incorporating an ultra-wide-bandgap β-Ga 2 O 3 semiconductor and dissimilar ferromagnetic electrodes (CoFeB and La 0.7 Sr 0.3 MnO 3 ). Using a tight-binding model combined with the non-equilibrium Green's function (NEGF) method, we analyze spin-dependent quantum transport under thermal gradients. The asymmetric design introduces sharp resonant-tunneling states within β-Ga 2 O 3 layer, enabling energy-selective spin transport and enhanced spin filtering. Compared to single-barrier MTJs and symmetric RT-MTJs, A-RT-MTJs exhibit improvements in TE properties due to amplified energy filtering and suppressed thermal conductivity. These results demonstrate that A-RT-MTJs with tailored resonant states and material asymmetry offer a promising pathway for high-efficiency thermal-to-spin energy conversion, advancing applications in spincaloritronic devices.