Abstract
In cuprate superconductors, superconductivity is accompanied by a plethora of orders and phenomena that complicate our understanding of superconductivity in these materials. Prominent in the underdoped regime, these orders weaken or vanish with overdoping. Here, we approach the superconducting phase from the more conventional overdoped side. We present angle-resolved photoemission spectroscopy studies of Bi_{2}Sr_{2}CaCu_{2}O_{8+delta }, cleaved and annealed in ozone to increase the doping all the way to the non-superconducting phase. We show that the mass renormalization in the antinodal region of the Fermi surface that possibly reflects the pairing, weakens with doping and completely disappears precisely where superconductivity disappears. This is the evidence that in the overdoped regime, superconductivity is determined primarily by the coupling strength. A doping dependence and an abrupt disappearance above the transition temperature eliminate phononic mechanism of the observed renormalization and identify the onset of spin-fluctuations as its likely origin.
Highlights
In cuprate superconductors, superconductivity is accompanied by a plethora of orders and phenomena that complicate our understanding of superconductivity in these materials
Parent compounds of cuprate superconductors are antiferromagnetically ordered Mott insulators wherein conduction and superconductivity are induced by doping additional holes or electrons away from the half-filled case[11]
We perform angleresolved photoemission spectroscopy (ARPES) studies in the overdoped regime of Bi2212 and discover the mass renormalization of antinodal electrons that indicates a coupling to some bosonic-like mode
Summary
Superconductivity is accompanied by a plethora of orders and phenomena that complicate our understanding of superconductivity in these materials. We show that the mass renormalization in the antinodal region of the Fermi surface that possibly reflects the pairing, weakens with doping and completely disappears precisely where superconductivity disappears. This is the evidence that in the overdoped regime, superconductivity is determined primarily by the coupling strength. The observation of renormalization effects in the low-energy electronic excitations in angleresolved photoemission spectroscopy (ARPES) has re-ignited the hope that a bosonic mode playing a role in pairing in cuprates could be identified, in analogy with how tunneling experiments provided the smoking gun evidence for phononic mechanism in conventional superconductors[1]. The doping and temperature dependences eliminate phononic mechanism of the observed renormalization and identify the onset of spin-fluctuations as its likely origin
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