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The structural and electronic properties of the 1T-SnS2/MoTe2 heterostructure were investigated based on density functional theory and Berry curvature calculations. Considering the strong spin–orbit coupling and space inversion asymmetry, large...

Based on first-principles calculations, the unconventional Rashba- and Zeeman-type spin splitting can simultaneously coexist in the Pb-adsorbed monolayer WSe2 system. The first two adsorption configurations t 1 and t 2 show remarkable features under the spin–orbit coupling, in which two split energy branches show same spin states at the left or right side of Γ, and the spin polarization is reversed for both Rashba band branches. For the second adsorption configuration, an energy gap was observed near the unconventional spin polarization caused by the repelled Rashba bands for avoid crossing, and this gap can produce non-dissipative spin current by applying the voltage. The results for t 2 configuration with spin reversal show that the repel band gap and Rashba parameter can be effectively regulated within the biaxial strain range of −8% to 6%. By changing the adsorption distance d between Pb and the neighboring Se atom layer, the reduced d caused the transfer from Rashba-type to Zeeman-type spin splitting. This predicted adsorption system would be promising for spintronic applications.

The electronic structure, phonons, and thermoelectric transport characteristics of NbXGe (X = Rh, Ir) half-Heusler compounds have been investigated using the first principles based on density functional theory. These alloys show semiconducting character with 18-valence electrons per unit cell following the Slater-Pauling rule. The band gaps of NbRhGe and NbIrGe are 0.65 and 0.63 eV, respectively. The good thermoelectric properties are achieved by applying lattice strains. NbRhGe obtains the ZT value of 0.87 at 300 K at the strain of − 6% gaining a double enhancement compared with the unstrained case, and NbIrGe obtains the ZT value of 0.74 at 300 K at the strain of 6% gaining a 12% enhancement compared with the unstrained case. Moreover, the NbXGe (X = Rh, Ir) half-Heusler compounds with a special quasi-random structure have been modeled to simulate the inevitable atomic occupation disorder between two sublattices. The maximum ZT values of NbIrGe and NbRhGe with SQS are 1.01 (300 K) and 0.83 (1250 K), respectively, which are higher than their corresponding structure of ordered occupation (0.66 and 0.78, respectively). Our results indicate that NbXGe (X = Rh, Ir) should be good thermoelectric candidate materials.