Cohesion properties of W/La₂O₃ interfaces from first principles calculation

First principles calculation reveals that the La-rich La₂O₃(0001) surface has much lower work function than the W(110) surface, which fundamentally improves the electron emission properties of W-La₂O₃ materials. Calculation also shows that the chemical potential of oxygen (μ_O) has an important effect on interface cohesion, i.e., the oxygen-rich and La-rich W(110)/La₂O₃(0001) interfaces are energetically more favorable with higher interface strength when -8.93 eV<μ_O≤ -4.89 eV and -10.79 eV≤μ_O≤ -8.93 eV, respectively. Moreover, it is found that the addition of La₂O₃ in W should lower the cohesion strength of W atoms, and the W/La₂O₃ interfaces or La₂O₃ particles would be the fracture positions in W-La₂O₃ materials. The bond analysis and electronic structures provide a deep understanding to various interface properties, and the calculated results are in excellent agreement with experimental observations.