Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of the Physical Society of Japan

Experimental Studies on Cooper Pair Transport in Josephson Junction Arrays

Takahide Yamaguchi, Hisao Miyazaki, Akinobu Kanda, Youiti Ootuka

Published Jan 3, 2003• 1 citation
Publisher

Abstract

We have investigated how the transport properties of small-Josephson-junction arrays vary depending on a quantum control parameter (the ratio of the Josephson coupling energy E J to the charging energy E C ), the magnitude of dissipation, and the dimensionality d of the system. We found that the arrays show Coulomb blockade behavior when R S is larger than about d R Q ( R Q ≡ h /4 e 2 =6.45 kΩ) and E J / E C is smaller than a threshold depending on the value of R S and the dimensionality. The result is discussed in terms of quantum phase transition induced by the charging effect and the dissipation.

DOI
10.1143/jpsjs.72sa.96

Related papers

Single Cooper-pair tunneling in small-capacitance junctions

Lambert J. Geerligs, V.F. Anderegg, J. Romijn +1 more

We present observations of charging effects for Cooper pairs in short linear arrays of small-capacitance Josephson junctions. Current-voltage characteristics show a Coulomb gap for Cooper-pair tunneling when the charging energy exceeds the Josephson coupling energy. In a double junction a zero-voltage current is observed that is modulated by a gate voltage applied to the metal island between the junctions. For longer arrays a crossover from Coulomb blockade of Cooper-pair tunneling to a supercurrent is observed when the ratio of Josephson coupling to charging energy is increased.

Physical Review Letters•Jul 16, 1990•101 citations

Experimental investigation of two-dimensional arrays of ultrasmall Josephson junctions

C. D. Chen, Per Delsing, David B. Haviland +1 more

We have measured Current-Voltage ( I-V ) characteristics of a large number of two-dimensional arrays of small area Al-AlOx-Al junctions down to temperatures of 40 mK, recording the temperature dependence of the zero bias resistance R 0 ( T ). The normal state resistance of the junctions R N varies from 2 kΩ to 270 kΩ and the junction capacitance C from 0.2 f F to 2.2 f F. The arrays are classified into different types according to the E J / E c and the R Q / R N ratios, and mapped onto a parameter diagram. E J is the Josephson coupling energy, E c = e 2 /2 C is the charging energy, and R Q = h /4 e 2 = 6.5 kΩ is the quantum resistance. For low resistance arrays, R Q / R N >> 1 with E J / E c > 1, the Josephson current prevails and the arrays are superconducting. When R Q / R N << 1 and E J / E c < 1, the I-V characteristics show typical Coulomb blockade features. In an intermediate region where R Q / R N similar 0.4, E J / E c similar 0.2, we find a "back-bending" I-V curve with negative differential resistance. The behavior of R 0 ( T ) also falls into three categories which can be correlated with the type of I-V characteristic. At the lowest temperature the arrays appear to be either insulating (d R 0 /d T < 0) or superconducting (d R 0 /d T > 0) depending on whether R N is greater than R Q or less than R Q respectively.

Physica Scripta•Jan 1, 1992•18 citations

Quantum effects in nanoscale Josephson junction circuits

S. Corlevi

This thesis presents the results of an experimental study on single-charge effects in nanoscale Josephson junctions and Cooper pair transistors (CPTs). In nanoscale Josephson junctions the charging energy EC becomes significant at sub-Kelvin temperatures and single-charge effects, such as the Coulomb blockade of Cooper pair tunneling, influence the transport properties. In order to observe charging effects in a single Josephson junction, the impedance of the electromagnetic environment surrounding the junction has to be larger than the quantum resistance (RQ=h/4e2≈6.45kΩ). In this work the high impedance environment is obtained by biasing the sample under test (single Josephson junction or CPT) with four one-dimensional Josephson junction arrays having SQUID geometry. The advantage of this configuration is the possibility of tuning in situ the effective impedance of the electromagnetic environment. By applying a magnetic field perpendicular to the SQUID loops, the Josephson energy EJ of the SQUIDs is suppressed, resulting in an increase of the measured zero bias resistance of the arrays of several orders of magnitude (104< R0 (Ω) <109). This bias method enables the measurement of the same sample in environments with different impedance. As the impedance of the environment is increased, the current-voltage characteristics (IVCs) of the single Josephson junction and of the CPT show a well defined Coulomb blockade feature with a region of negative differential resistance, signature of the coherent tunneling of single Cooper pairs. The measured IVCs of a single Josephson junction with SQUID geometry in the high impedance environment show a qualitative agreement with the Bloch band theory as the EJ/EC ratio of the junction is tuned with the magnetic field. We also studied a single nontunable Josephson junction with strong coupling (EJ/EC > 1), where the exact dual of the overdamped Josephson effect is realized, resulting in a dual shape of the IVC, where the roles of current and voltage are exchanged. Here, we make for the first time a detailed quantitative comparison with a theory which includes the effect of fluctuations due to the finite temperature of the environment. The measurements on CPTs in the high impedance environment showed that the Coulomb blockade voltage is modulated periodically by the gate-induced charge. The gate-voltage dependence of the CPT changes from e-periodic to 2e-periodic as the impedance of the environment is increased. The high impedance environment reduces quasiparticle tunneling rates, thereby restoring the even parity of the CPT island. This behavior suggests that high impedance leads can be used to effectively suppress quasiparticle poisoning.

•Jan 1, 2006•5 citations

Control of the electromagnetic environment for single Josephson junctions using arrays of dc SQUIDs

道生 渡部, David B. Haviland, Richard L. Kautz

We have measured the current–voltage characteristics of small-capacitance single Josephson junctions at low temperatures T ≤ 0.04 K, where the strength of the coupling between the single junction and the electromagnetic environment was controlled with one-dimensional arrays of dc SQUIDs. When the zero-bias resistance of the SQUID arrays is much higher than the quantum resistance h/e 2 ≈ 26 kΩ, a transition to a clear Coulomb blockade of Cooper-pair tunnelling is induced in the single junction. The measured blockade voltage agrees with the theoretical prediction.

Superconductor Science and Technology•Sep 25, 2001•6 citations

Charging effects and quantum coherence in regular Josephson junction arrays

Lambert J. Geerligs, M. Peters, L. E. M. de Groot +2 more

Two-dimensional arrays of very-small-capacitance Josephson junctions have been studied. At low temperatures the arrays show a transition from superconducting to insulating behavior when the ratio of charging energy to Josephson-coupling energy exceeds the value 1. Insulating behavior coincides withthe occurrence of a charging gap inside the BCS gap, with an S-shaped I-V characteristic. This so far unobserved S shape is predicted to arise from macroscopic quantum coherent effects including Bloch oscillations.

Physical Review Letters•Jul 17, 1989•242 citations

Coulomb blockade of Cooper pair tunneling and parity effects in the Cooper pair transistor

S. Corlevi, Wiebke Guichard, F. W. J. Hekking +1 more

We have measured the Cooper pair transistor (CPT) in a tunable electromagnetic environment consisting of four one-dimensional superconducting quantum interference device arrays. The transport properties of the CPT in the high impedance limit, ${Z}_{\mathrm{env}}⪢{R}_{Q}\ensuremath{\simeq}6.45\phantom{\rule{0.3em}{0ex}}\mathrm{k}\ensuremath{\Omega}$, are studied for different ratios of the Josephson coupling energy to the charging energy. As the impedance of the environment is increased, the current-voltage characteristic (IVC) of the CPT develops a Coulomb blockade of Cooper pair tunneling and the measured IVCs agree qualitatively with a theory based on quasicharge dynamics for a CPT. Increasing the impedance of the environment induces a transition in the modulation of the IVC with the gate charge from $e$-periodic to $2e$-periodic.

arXiv:cond-mat/0606407•Physical Review B•Dec 13, 2006•21 citations
We have investigated how the transport properties of small-Josephson-junction arrays vary depending on a quantum control parameter (the ratio of the Josephson coupling energy E J to the charging energy E C ), the magnitude of dissipation, and the dimensionality d of the system. We found that the arrays show Coulomb blockade behavior when R S is larger than about d R Q ( R Q ≡ h /4 e 2 =6.45 kΩ) and E J / E C is smaller than a threshold depending on the value of R S and the dimensionality. The result is discussed in terms of quantum phase transition induced by the charging effect and the dissipation.
We present observations of charging effects for Cooper pairs in short linear arrays of small-capacitance Josephson junctions. Current-voltage characteristics show a Coulomb gap for Cooper-pair tunneling when the charging energy exceeds the Josephson coupling energy. In a double junction a zero-voltage current is observed that is modulated by a gate voltage applied to the metal island between the junctions. For longer arrays a crossover from Coulomb blockade of Cooper-pair tunneling to a supercurrent is observed when the ratio of Josephson coupling to charging energy is increased.
We have measured Current-Voltage ( I-V ) characteristics of a large number of two-dimensional arrays of small area Al-AlOx-Al junctions down to temperatures of 40 mK, recording the temperature dependence of the zero bias resistance R 0 ( T ). The normal state resistance of the junctions R N varies from 2 kΩ to 270 kΩ and the junction capacitance C from 0.2 f F to 2.2 f F. The arrays are classified into different types according to the E J / E c and the R Q / R N ratios, and mapped onto a parameter diagram. E J is the Josephson coupling energy, E c = e 2 /2 C is the charging energy, and R Q = h /4 e 2 = 6.5 kΩ is the quantum resistance. For low resistance arrays, R Q / R N >> 1 with E J / E c > 1, the Josephson current prevails and the arrays are superconducting. When R Q / R N << 1 and E J / E c < 1, the I-V characteristics show typical Coulomb blockade features. In an intermediate region where R Q / R N similar 0.4, E J / E c similar 0.2, we find a "back-bending" I-V curve with negative differential resistance. The behavior of R 0 ( T ) also falls into three categories which can be correlated with the type of I-V characteristic. At the lowest temperature the arrays appear to be either insulating (d R 0 /d T < 0) or superconducting (d R 0 /d T > 0) depending on whether R N is greater than R Q or less than R Q respectively.
This thesis presents the results of an experimental study on single-charge effects in nanoscale Josephson junctions and Cooper pair transistors (CPTs). In nanoscale Josephson junctions the charging energy EC becomes significant at sub-Kelvin temperatures and single-charge effects, such as the Coulomb blockade of Cooper pair tunneling, influence the transport properties. In order to observe charging effects in a single Josephson junction, the impedance of the electromagnetic environment surrounding the junction has to be larger than the quantum resistance (RQ=h/4e2≈6.45kΩ). In this work the high impedance environment is obtained by biasing the sample under test (single Josephson junction or CPT) with four one-dimensional Josephson junction arrays having SQUID geometry. The advantage of this configuration is the possibility of tuning in situ the effective impedance of the electromagnetic environment. By applying a magnetic field perpendicular to the SQUID loops, the Josephson energy EJ of the SQUIDs is suppressed, resulting in an increase of the measured zero bias resistance of the arrays of several orders of magnitude (104< R0 (Ω) <109). This bias method enables the measurement of the same sample in environments with different impedance. As the impedance of the environment is increased, the current-voltage characteristics (IVCs) of the single Josephson junction and of the CPT show a well defined Coulomb blockade feature with a region of negative differential resistance, signature of the coherent tunneling of single Cooper pairs. The measured IVCs of a single Josephson junction with SQUID geometry in the high impedance environment show a qualitative agreement with the Bloch band theory as the EJ/EC ratio of the junction is tuned with the magnetic field. We also studied a single nontunable Josephson junction with strong coupling (EJ/EC > 1), where the exact dual of the overdamped Josephson effect is realized, resulting in a dual shape of the IVC, where the roles of current and voltage are exchanged. Here, we make for the first time a detailed quantitative comparison with a theory which includes the effect of fluctuations due to the finite temperature of the environment. The measurements on CPTs in the high impedance environment showed that the Coulomb blockade voltage is modulated periodically by the gate-induced charge. The gate-voltage dependence of the CPT changes from e-periodic to 2e-periodic as the impedance of the environment is increased. The high impedance environment reduces quasiparticle tunneling rates, thereby restoring the even parity of the CPT island. This behavior suggests that high impedance leads can be used to effectively suppress quasiparticle poisoning.
We have measured the current–voltage characteristics of small-capacitance single Josephson junctions at low temperatures T ≤ 0.04 K, where the strength of the coupling between the single junction and the electromagnetic environment was controlled with one-dimensional arrays of dc SQUIDs. When the zero-bias resistance of the SQUID arrays is much higher than the quantum resistance h/e 2 ≈ 26 kΩ, a transition to a clear Coulomb blockade of Cooper-pair tunnelling is induced in the single junction. The measured blockade voltage agrees with the theoretical prediction.
Two-dimensional arrays of very-small-capacitance Josephson junctions have been studied. At low temperatures the arrays show a transition from superconducting to insulating behavior when the ratio of charging energy to Josephson-coupling energy exceeds the value 1. Insulating behavior coincides withthe occurrence of a charging gap inside the BCS gap, with an S-shaped I-V characteristic. This so far unobserved S shape is predicted to arise from macroscopic quantum coherent effects including Bloch oscillations.
We have measured the Cooper pair transistor (CPT) in a tunable electromagnetic environment consisting of four one-dimensional superconducting quantum interference device arrays. The transport properties of the CPT in the high impedance limit, ${Z}_{\mathrm{env}}⪢{R}_{Q}\ensuremath{\simeq}6.45\phantom{\rule{0.3em}{0ex}}\mathrm{k}\ensuremath{\Omega}$, are studied for different ratios of the Josephson coupling energy to the charging energy. As the impedance of the environment is increased, the current-voltage characteristic (IVC) of the CPT develops a Coulomb blockade of Cooper pair tunneling and the measured IVCs agree qualitatively with a theory based on quasicharge dynamics for a CPT. Increasing the impedance of the environment induces a transition in the modulation of the IVC with the gate charge from eee-periodic to 2e2e2e-periodic.