J.K. Kawasaki, C.H. Kim, J.N. Nelson, S. Crisp, C.J. Zollner, E. Bigenwald, J.T. Heron, C.J. Fennie, D.G. Schlom, and K.M. Shen, “Engineering Carrier Effective Masses in Ultrathin Quantum Wells of IrO2,” Physical Review Letters 121 (2018) 176802-1 – 176802-6.