The influence of coulomb potential fluctuation on c-axis tunneling in cuprates

Pham, Minh T.

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https://hdl.handle.net/2142/46715 Copy

Description

Title

The influence of coulomb potential fluctuation on c-axis tunneling in cuprates

Author(s)

Pham, Minh T.

Issue Date

2014-01-16T18:00:04Z

Director of Research (if dissertation) or Advisor (if thesis)

Leggett, Anthony J.

Doctoral Committee Chair(s)

Phillips, Philip W.

Committee Member(s)

• Leggett, Anthony J.
• Greene, Laura H.
• Stack, John D.

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• cuprate
• c-axis resistivity
• Coulomb fluctuation
• point-to-point tunneling model
• random-phase approximation (RPA)
• tunneling

Abstract

The subject of this thesis is studying the resistivity along c-axis direction in cuprates, layered high-temperature superconducting materials as a function of temperature. A point-to-point tunneling model is built to describe the tunneling between two CuO2 planes including the in-plane Coulomb interaction. With a general assumption that the spectral function of the Coulomb uctuation is ohmic, the solution of the transmission rate in the model is obtained by mapping the Coulomb potential fluctuation to phonon coupling of the spin-boson model. From the result of the transmission rate, the c-axis resistivity is calculated in both gapless and gap cases as a function of the temperature and the strength of the Coulomb uctuation. The dimensionless parameter characterizing the strength of the Coulomb uctuation is calculated theoretically in the random-phase approximation (RPA) and in the Landau-Fermi liquid theory. The extensions of the calculation to include the Coulomb interaction between CuO2 planes are done in this thesis to get a better description of c-axis transport for double-layered cuprates and single-layered cuprates. It turns out the theoretical form of the c-axis resistivity ts quite well with experimental data in both the metallic (gapless) region and the metal-insulator crossover (pseudogap) region of the c-axis resistivity. The parameter in the tting is also compared with the solution in the RPA calculation. It shows that the RPA result of is reasonably good in gapless case but fails in gap case. An extension for the future work about a multi-channel tunneling model is discussed in the last part of the thesis.

Graduation Semester

2013-12

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http://hdl.handle.net/2142/46715

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Copyright 2013 Minh Tuan Pham

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