Artificial two-dimensional polar metal at room temperature
Abstract
Polar metals, commonly defined by the coexistence of polar crystal structure and metallicity, are thought to be scarce because the long-range electrostatic fields favoring the polar structure are expected to be fully screened by the conduction electrons of a metal. Moreover, reducing from three to two dimensions, it remains an open question whether a polar metal can exist. Here we report on the realization of a room temperature two-dimensional polar metal of the B-site type in tri-color (tri-layer) superlattices BaTiO/SrTiO/LaTiO. A combination of atomic resolution scanning transmission electron microscopy with electron energy loss spectroscopy, optical second harmonic generation, electrical transport, and first-principles calculations have revealed the microscopic mechanisms of periodic electric polarization, charge distribution, and orbital symmetry. Our results provide a route to creating all-oxide artificial non-centrosymmetric quasi-two-dimensional metals with exotic quantum states including coexisting ferroelectric, ferromagnetic, and superconducting phases.
Cite
@article{arxiv.1804.05487,
title = {Artificial two-dimensional polar metal at room temperature},
author = {Yanwei Cao and Zhen Wang and Se Young Park and Yakun Yuan and Xiaoran Liu and Sergey M. Nikitin and Hirofumi Akamatsu and M. Kareev and S. Middey and D. Meyers and P. Thompson and P. J. Ryan and Padraic Shafer and A. N'Diaye and E. Arenholz and Venkatraman Gopalan and Yimei Zhu and Karin M. Rabe and J. Chakhalain},
journal= {arXiv preprint arXiv:1804.05487},
year = {2018}
}