Record high $T_{\mathrm{c}}$ and robust superconductivity in transition metal $\delta$-Ti phase at megabar pressure

Abstract

We report a record high superconducting transition temperature ($T_{\mathrm{c}}$) up to 23.6 K under high pressure in the elemental metal Ti, one of the top ten most abundant elements in Earth's crust. The $T_{\mathrm{c}}$ increases monotonically from 2.3 K at 40.3 GPa to 23.6 K at 144.9 GPa, which surpasses all known records from elemental metals reported so far. With further compression, a robust $T_{\mathrm{c}}$ of ~23 K is observed between 144.9 and 183 GPa in the $\delta$-Ti phase. The pressure-dependent $T_{\mathrm{c}}$ can be well described by the conventional electron-phonon coupling (EPC) mechanism. Density Functional Theory calculations show the Fermi nesting and the phonon softening of optical branches at the $\gamma$-Ti to $\delta$-Ti phase transition pressure enhance EPC, which results in the record high $T_{\mathrm{c}}$. We attribute the robust superconductivity in $\delta$-Ti to the apparent robustness of its strong EPC against lattice compression. These results provide new insight into exploring new high-$T_{\mathrm{c}}$ elemental metals and Ti-based superconducting alloys.

References in corpus (4)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Pressure induced superconductivity in Bi single crystals
• Enhanced magnetic ordering in Sm metal under extreme pressure
• Linear response results for phonons and electron-phonon coupling in hcp Sc - spin fluctuations and implications for superconductivity

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