Pressure-Induced Superconductivity in the Charge-Density-Wave Compound LaTe2-xSbx(x=0 and 0.4)

Magnetic CeTe2 achieving superconductivity under external pressure has received considerable attention.The intermingling of 4f and 5d electrons from Ce raised the speculation of an unconventional pairing mechanism aris-ing from magnetic fluctuations.Here,we address this speculation using a nonmagnetic 4f-electron-free LaTe2 as an example.No structural phase transition can be observed up to 35 GPa in the in situ synchrotron diffrac-tion patterns.Subsequent high-pressure electrical measurements show that LaTe2 exhibits superconductivity at 20 Gpa with its Tc(4.5 K)being two times higher than its Ce-counterpart.Detailed theoretical calculations reveal that charge transfer from the 4p orbitals of the planar square Te-Te network to the 5d orbitals of La is responsible for the emergence of superconductivity in LaTe2,as confirmed by Hall experiments.Furthermore,we study the modulation of qCDW by Sb substitution and find a record high Tonset～6.5 K in LaTe1.6Sb0.4.Our work provides an informative clue to comprehend the role of 5d-4p hybridization in the relationship between charge density wave(CDW)and superconductivity in these RETe2(RE=rare-earth elements)compounds.