Stress can make lattice shrink, increase energy band overlap, destroy this balance between carriers, which may induce a new electronic phase transition. Based on this consideration, cooperation team at Nanjing University of Artificial Microstructure Collaborative Innovation Center under the framework of the research carried out quickly both experimental and theoretical high pressure.

 

It was found that: at a pressure of 2.7GPa, when the temperature dropped to 3.1K or less, along with the gradual disappearance of the giant magnetoresistance effect, there was a sharp decline of the resistance. With further increase of the pressure, the emergence of zero resistance appear gradually, indicating the resistance steep drop corresponds to a stress-induced superconducting transition. At about 17GPa, the superconducting transition temperature TC reaches the maximum of 7K, and the accompanying pressures continue to increase, TC gradually decreased, showing a phase diagrama of superconducting pressure as a "dome" type. The study of different external magnetic field at high pressure resistance and magnetic susceptibility has been the further evidence of the existence of superconductivity. On the other hand, Theoretical calculations of high-pressure related show that TC beginning to increase with increasing pressure is the results of increasing density of states near the Fermi surface, and decreases of TC under higher pressure is attributed to the lattice structure instability.