Self-doping in Sr2VO4/Sr2IrO4 superlattice*

Searching for high transition temperature superconductivity in non-cuprate materials has always been one of the focus topics in condensed matter physics. Theoretically, Sr2IrO4 has been proposed as a promising candidate to induce high Tc superconductivity because of the similarity of its electronic structure to that of cuprates [1]. Experimentally, surface-electron doped Sr2IrO4 exhibits spectroscopic signatures that are consistent with a superconducting gap but a zero-resistance state is yet to be found [2,3]. Here we artificially design a Sr2VO4/Sr2IrO4 superlattice, composed of VO2 layer and IrO2 layer alternating along the c-axis. Our ab initio calculations show that only V-dxy band and Ir-J=1/2 band cross the fermi level, forming a coupled two-dimensional Hubbard model with self-doping. The superlattice can be used as an effective way to electron dope iridates without introducing chemical disorder.
[1] Wang F, Senthil T., Physical Review Letters, 2011, 106(13): 136402.
[2] Yan Y J, Ren M Q, Xu H C, et al., Physical Review X, 2015, 5(4): 041018.
[3] Kim Y K, Sung N H, Denlinger J D, et al., Nature Physics, 2016, 12(1): 37.