Most of the superconductors with nontrivial band topology discovered so far are constrained to materials with low superconducting transition temperatures $\left(T_{\mathrm{c}}\right)$ and narrow topological energy gaps. Here we use first-principles calculations to demonstrate that ${\mathrm{KTeO}}_3$ can be converted into high-$T_{\mathrm{c}}$ superconductors with concomitant large topological energy gaps via effective suppression of the multivalency of Te. We first show that the inherent multivalent nature of Te in pristine ${\mathrm{KTeO}}_3$, accompanied by too strong electron-phonon coupling, leads to a dominant charge density wave (CDW) instability. Next, we find that when the Te multivalency is suppressed by proper gating or partially substituting K with Ba at moderate pressure, the electron-phonon coupling is significantly weakened, and the CDW instability yields to a dominant superconducting order with a maximum $T_{\mathrm{c}}$ of ∼60 K right at the CDW-to-superconductivity transition. Furthermore, the superconducting systems exhibit nontrivial band topology with unusually wide energy gaps of ∼0.8 eV, thereby serving as appealing platforms for realizing topological superconductivity with exceptional robustness and tunability.

Close

PrevNext

View figure in article

• Charge density waves
• First-principles calculations
• Superconductors
• Surface states
• Topological materials