Fig. 1: Electrical resistivity and P-T phase diagram of Y at different pressures.

a Pressure–temperature evolution of the resistivity of Y. The inset displays the resistivity over the entire temperature range (6–300 K) at which measurements were conducted at various pressures up to 109.4 GPa. b P-T phase diagram of Y obtained from resistivity (circle symbols) and ac susceptibility (square symbols) measurements under pressure. The star symbols refer to our resistivity data in the symmetric cell (blue) and miniature Be-Cu cell (red). The resistivity measurements of T_c from references^10,12 are represented as navy and olive circles, respectively. T_c collected from ac susceptibility measurements is indicated by square symbols^5,11. The dashed lines indicate the structural phase boundaries measured at room temperature¹³. As the pressure increases, the phase transition sequence for the crystal structure is hcp–α-Sm type–dhcp–dfcc–oF16. The inset shows a photograph of the van der Pauw configuration at 109.4 GPa.