Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition

N. P. Armitage; R. W. Crane; G. Sambandamurthy; A. Johansson; D. Shahar; V. Zaretskey; G. Grüner

doi:10.1016/j.physb.2007.10.253

Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition

N. P. Armitage
, R. W. Crane
, G. Sambandamurthy
, A. Johansson
, D. Shahar
, V. Zaretskey
, G. Grüner

Physics

Johns Hopkins University
Weizmann Institute of Science
University of California at Los Angeles

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

We review our recent measurements of the complex AC conductivity of thin InO_x films studied as a function of magnetic field through the nominal 2D superconductor-insulator transition. These measurements-the first to probe anything other than the ω = 0 response of these archetypical systems-reveal a significant finite frequency superfluid stiffness well into the insulating regime. Unlike conventional fluctuation superconductivity in which thermal fluctuations can give a superconducting response in regions of parameter space that do not exhibit long range order, these fluctuations are temperature independent as T → 0 and are exhibited in samples where the resistance is large (greater than 10⁶ Ω / □) and strongly diverging. We interpret this as the first direct observation of quantum superconducting fluctuations around an insulating ground state. This system serves as a prototype for other insulating states of matter that derive from superconductors.

Original language	English
Pages (from-to)	1208-1210
Number of pages	3
Journal	Physica B: Condensed Matter
Volume	403
Issue number	5-9
DOIs	https://doi.org/10.1016/j.physb.2007.10.253
State	Published - Apr 1 2008

Keywords

2D superconductor-insulator
AC conductivity
Quantum fluctuations
Quantum phase transition

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10.1016/j.physb.2007.10.253

Cite this

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title = "Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition",

abstract = "We review our recent measurements of the complex AC conductivity of thin InOx films studied as a function of magnetic field through the nominal 2D superconductor-insulator transition. These measurements-the first to probe anything other than the ω = 0 response of these archetypical systems-reveal a significant finite frequency superfluid stiffness well into the insulating regime. Unlike conventional fluctuation superconductivity in which thermal fluctuations can give a superconducting response in regions of parameter space that do not exhibit long range order, these fluctuations are temperature independent as T → 0 and are exhibited in samples where the resistance is large (greater than 106 Ω / □) and strongly diverging. We interpret this as the first direct observation of quantum superconducting fluctuations around an insulating ground state. This system serves as a prototype for other insulating states of matter that derive from superconductors.",

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AU - Armitage, N. P.

AU - Crane, R. W.

AU - Sambandamurthy, G.

AU - Johansson, A.

AU - Shahar, D.

AU - Zaretskey, V.

AU - Grüner, G.

PY - 2008/4/1

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N2 - We review our recent measurements of the complex AC conductivity of thin InOx films studied as a function of magnetic field through the nominal 2D superconductor-insulator transition. These measurements-the first to probe anything other than the ω = 0 response of these archetypical systems-reveal a significant finite frequency superfluid stiffness well into the insulating regime. Unlike conventional fluctuation superconductivity in which thermal fluctuations can give a superconducting response in regions of parameter space that do not exhibit long range order, these fluctuations are temperature independent as T → 0 and are exhibited in samples where the resistance is large (greater than 106 Ω / □) and strongly diverging. We interpret this as the first direct observation of quantum superconducting fluctuations around an insulating ground state. This system serves as a prototype for other insulating states of matter that derive from superconductors.

AB - We review our recent measurements of the complex AC conductivity of thin InOx films studied as a function of magnetic field through the nominal 2D superconductor-insulator transition. These measurements-the first to probe anything other than the ω = 0 response of these archetypical systems-reveal a significant finite frequency superfluid stiffness well into the insulating regime. Unlike conventional fluctuation superconductivity in which thermal fluctuations can give a superconducting response in regions of parameter space that do not exhibit long range order, these fluctuations are temperature independent as T → 0 and are exhibited in samples where the resistance is large (greater than 106 Ω / □) and strongly diverging. We interpret this as the first direct observation of quantum superconducting fluctuations around an insulating ground state. This system serves as a prototype for other insulating states of matter that derive from superconductors.

KW - 2D superconductor-insulator

KW - AC conductivity

KW - Quantum fluctuations

KW - Quantum phase transition

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DO - 10.1016/j.physb.2007.10.253

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JO - Physica B: Condensed Matter

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Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition

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