Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?

Sep. 29 (Thu), 4:00 PM, E6-2. #2501(2nd fl.)
Dr. Minu Kim, Institute for Basic Science, Seoul National University

Recently, we found novel routes to experimentally control the phase diagram in the perovskite bismuthate BaBiO3 (BBO), the parent compound of several high-Tc oxide superconductors. Numerous experimental and theoretical studies have sought to gain insight into the mechanisms that control the physics of these bismuthates [1,2]; to date, however, only limited progress has been made in hole-doped bulk samples. Here, we present our recent progress on exploration of the novel phase diagram of BBO via thickness and doping controls. We revealed that a minimum length scale to sustain a charge density wave order in BBO films by thickness control [3]. Furthermore, the electronic and structural properties of BBO were strongly dependent on oxygen deficiency, disclosed by the combination of in situ spectroscopic techniques and first-principles calculations. Our approaches introduce independent control parameters to explore the BBO phase diagram, and may also provide a useful guideline to study the recently predicted topological phases in electron-doped bismuthates [4].

[1] A. W. Sleight, J. L. Gillson, P. E. Bierstedt, Solid State Commun. 17, 27 (1975)
[2] R. J. Cava et al., Nature 328, 814 (1988)
[3] G. Kim et al., Phys. Rev. Lett. 115, 226402 (2015)
[4] B. Yan et al., Nat. Phys. 9, 709 (2013)

Contact: MyungJoon Han, Physics Dept., (mj.han@kaist.ac.kr)