title: Thermal stability of mullite RMn₂O₅ (R  =  Bi, Y, Pr, Sm or Gd): combined density functional theory and experimental study.
abstract: Understanding and effectively predicting the thermal stability of ternary transition metal oxides with heavy elements using first principle simulations are vital for understanding performance of advanced materials. In this work, we have investigated the thermal stability of mullite RMn2O5 (R  =  Bi, Pr, Sm, or Gd) structures by constructing temperature phase diagrams using an efficient mixed generalized gradient approximation (GGA) and the GGA  +  U method. Simulation predicted stability regions without corrections on heavy elements show a 4-200 K underestimation compared to our experimental results. We have found the number of d/f electrons in the heavy elements shows a linear relationship with the prediction deviation. Further correction on the strongly correlated electrons in heavy elements could significantly reduce the prediction deviations. Our corrected simulation results demonstrate that further correction of R-site elements in RMn2O5 could effectively reduce the underestimation of the density functional theory-predicted decomposition temperature to within 30 K. Therefore, it could produce an accurate thermal stability prediction for complex ternary transition metal oxide compounds with heavy elements.
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Chenzhe
authors.initials: C
authors.lastname: Li
authors.forename: Sampreetha
authors.initials: S
authors.lastname: Thampy
authors.forename: Yongping
authors.initials: Y
authors.lastname: Zheng
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Kweun
authors.forename: Yixin
authors.initials: Y
authors.lastname: Ren
authors.forename: Julia Y
authors.initials: JY
authors.lastname: Chan
authors.forename: Hanchul
authors.initials: H
authors.lastname: Kim
authors.forename: Maenghyo
authors.initials: M
authors.lastname: Cho
authors.forename: Yoon Young
authors.initials: YY
authors.lastname: Kim
authors.forename: Julia W P
authors.initials: JW
authors.lastname: Hsu
authors.forename: Kyeongjae
authors.initials: K
authors.lastname: Cho