M. A. Continentino

Publications (4)7.37 Total impact

• Article: Superconducting quantum critical point in CeCoIn(5-x)Sn(x).

  S M Ramos, M B Fontes, E N Hering, M A Continentino, E Baggio-Saitovich, F Dinóla Neto, E M Bittar, P G Pagliuso, E D Bauer, J L Sarrao, J D Thompson
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  ABSTRACT: We report a combined pressure-doping study in the nearly two-dimensional heavy fermion superconductor CeCoIn5 as its superconducting phase is driven to the normal state by Sn doping and/or applied pressure. Temperature-pressure-dependent electrical resistivity measurements were performed at the vicinity of a superconducting quantum critical point where Tc→0. A universal plot of the concentration- and pressure-dependent phase diagram suggests that for the concentrations studied a single mechanism is responsible for reducing Tc and bringing the system to the superconducting quantum critical point. A two-band model with hybridization controlled by pressure and doping provides a consistent description of the phase diagram and the suppression of the d-wave superconductivity in this material.
  Physical Review Letters 09/2010; 105(12):126401. · 7.37 Impact Factor
• Source

  Available from: arxiv.org

  Article: First order quantum phase transitions

  M. A. Continentino, A. S. Ferreira
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  ABSTRACT: Quantum phase transitions have been the subject of intense investigations in the last two decades [1]. Among other problems, these phase transitions are relevant in the study of heavy fermion systems, high temperature superconductors and Bose-Einstein condensates. More recently there is increasing evidence that in many systems which are close to a quantum critical point (QCP) different phases are in competition. In this paper we show that the main effect of this competition is to give rise to inhomogeneous behavior associated with quantum first order transitions. These effects are described theoretically using an action that takes into account the competition between different order parameters. The method of the effective potential is used to calculate the quantum corrections to the classical functional. These corrections generally change the nature of the QCP and give rise to interesting effects even in the presence of non-critical fluctuations. An unexpected result is the appearance of an inhomogeneous phase with two values of the order parameter separated by a first order transition. Finally, we discuss the universal behavior of systems with a weak first order zero temperature transition in particular as the transition point is approached from finite temperatures. The thermodynamic behavior along this line is obtained and shown to present universal features.
  11/2006;
• Source

  Available from: arxiv.org

  Article: Quantum corrections to the phase diagram of heavy-fermion superconductors

  A. S. Ferreira, M. A. Continentino, E. C. Marino
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  ABSTRACT: The competition between magnetism and Kondo effect is the main effect determining the phase diagram of heavy fermion systems. It gives rise to a quantum critical point which governs the low temperature properties of these materials. However, experimental results made it clear that a fundamental ingredient is missing in this description, namely superconductivity. In this paper we make a step forward in the direction of incorporating superconductivity and study the mutual effects of this phase and antiferromagnetism in the phase diagram of heavy fermion metals. Our approach is based on a Ginzburg-Landau theory describing superconductivity and antiferromagnetism in a metal with quantum corrections taken into account through an effective potential. The proximity of an antiferromagnetic instability extends the region of superconductivity in the phase diagram and drives this transition into a first order one. On the other hand superconducting quantum fluctuations near a metallic antiferromagnetic quantum critical point gives rise to a first order transition from a low moment to a high moment state in the antiferromagnet. Antiferromagnetism and superconductivity may both collapse at a quantum bicritical point whose properties we calculate. Comment: 10 pages, 6 figures
  03/2005;
• Source

  Available from: arxiv.org

  Article: Solid state Pomeranchuk effect

  M. A. Continentino, A. S. Ferreira, P. G. Pagliuso, C. Rettori, J. L. Sarrao
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  ABSTRACT: Recently we have shown that $YbInCu_4$ and related compounds present a solid state Pomeranchuk effect. These systems have a first order volume transition where a local moment phase coexists with a renormalized Fermi liquid in analogy with $^3He$ at its melting curve. We demonstrate here experimentally that the solid state Pomeranchuk effect, controlled by a magnetic field, can be used to produce cooling. Comment: 2 pages, 3 figures, to be published in the Proceedings of SCES04 Conference, PHYSICA B
  08/2004;