Doping Controlled Superconductor-Insulator Transition in Bi2Sr2-xLaxCaCu2O8+delta

TL;DR

This study investigates the doping-controlled superconductor-insulator transition in a high-Tc cuprate, revealing unconventional behavior with diverging resistance at critical doping and a two-component conductance model indicating phase separation.

Contribution

It demonstrates a fundamentally different superconductor-insulator transition in Bi2Sr2-xLaxCaCu2O8+delta, highlighting a collective phase separation mechanism not seen in conventional models.

Findings

Resistance diverges at critical doping in the zero temperature limit.

Transport behavior scales with a two-component conductance model.

Insulating behavior evolves continuously from weak to strong insulator.

Abstract

We show that the doping-controlled superconductor-insulator transition (SIT) in a high critical temperature cuprate system (Bi2Sr2-xLaxCaCu2O8+delta) exhibits a fundamentally different behavior than is expected from conventional SIT. At the critical doping, the sheet resistance seems to diverge in the zero temperature limit. Above the critical doping, the transport is universally scaled by a two-component conductance model. Below, it continuously evolves from weakly to strongly insulating behavior. The two-component conductance model suggests that a collective electronic phase separation mechanism may be responsible for this unconventional SIT behavior.