Pressure-induced double superconducting domes and charge instability in the kagome metal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>KV</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Sb</mml:mi><mml:mn>5</mml:mn></mml:msub></mml:mrow></mml:math>
Feng Du, Shuaishuai Luo, Brenden R. Ortiz, Ye Chen, Weiyin Duan, Dongting Zhang, Xin Lu, Stephen D. Wilson, Yu Song, Huiqiu Yuan
Abstract
The kagome metal ${\mathrm{KV}}_{3}{\mathrm{Sb}}_{5}$ hosts charge order, topologically nontrivial Dirac band crossings, and a superconducting ground state with unconventional characteristics, providing an ideal platform to investigate the interplay between different electronic states on the kagome lattice. Here we study the evolution of charge order and superconductivity in ${\mathrm{KV}}_{3}{\mathrm{Sb}}_{5}$ under hydrostatic pressure using electrical resistivity measurements. With the application of pressure, the superconducting transition temperature ${T}_{\mathrm{c}}=0.9$ K under ambient pressure quickly increases to 3.1 K at $p=0.4$ GPa, as charge order progressively weakens. Upon further increasing pressure, signatures of charge order disappear at ${p}_{\mathrm{c}1}\ensuremath{\approx}0.5$ GPa and ${T}_{\mathrm{c}}$ is gradually suppressed, forming a superconducting dome that terminates at $p\ensuremath{\approx}10$ GPa. Beyond $p\ensuremath{\approx}10$ GPa, a second superconducting dome emerges with maximum ${T}_{\mathrm{c}}\ensuremath{\approx}1.0$ K at ${p}_{\mathrm{c}2}\ensuremath{\approx}22$ GPa, which becomes fully suppressed at $p\ensuremath{\approx}28$ GPa. The suppression of superconductivity for the second superconducting dome is associated with the appearance of a unique high-pressure phase, possibly a distinct charge order.