Topological transitions in multi-band superconductors

Continentino, M. A.; Deus, Fernanda; Padilha, Igor T.; Caldas, Heron

doi:10.1016/j.aop.2014.05.008

Cited by 14 publications

(18 citation statements)

References 38 publications

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“…The sp mixing is in a special class that mixes orbitals with angular momenta that differ by an odd number. This implies the anti-symmetric prop- [12].…”

Section: Introductionmentioning

confidence: 93%

Fermi points and topological quantum phase transitions in a multi-band superconductor

Puel¹,

Sacramento²,

Continentino³

2015

J. Phys.: Condens. Matter

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The importance of models with an exact solution for the study of materials with non-trivial topological properties has been extensively demonstrated. Among these, the Kitaev model of a one-dimensional p-wave superconductor plays a guiding role in the search for Majorana modes in condensed matter systems. Also, the sp chain, with an anti-symmetric mixing among the s and p bands provides a paradigmatic example of a topological insulator with well understood properties. There is an intimate relation between these two models and in particular their topological quantum phase transitions share the same universality class. Here we consider a two-band sp model of spinless fermions with an attractive (inter-band) interaction. Both the interaction and hybridization between the s and p fermions are anti-symmetric. The zero temperature phase diagram of the model presents a variety of phases including a Weyl superconductor, topological insulator and trivial phases. The quantum phase transitions between these phases can be either continuous or discontinuous. We show that the transition from the topological superconducting phase to the trivial one has critical exponents different from those of an equivalent transition in Kitaev's model.

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“…The sp mixing is in a special class that mixes orbitals with angular momenta that differ by an odd number. This implies the anti-symmetric prop- [12].…”

Section: Introductionmentioning

confidence: 93%

Fermi points and topological quantum phase transitions in a multi-band superconductor

Puel¹,

Sacramento²,

Continentino³

2015

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…There are at least three very interesting points to be noticed in these figures. First, the enhancement of superconductivity by antisymmetric hybridization which had already been noticed [13]. Second, the combined behavior of the chemical potential decreasing γ and the concomitant increase in∆ ab is a clear signature of a BCS-BEC crossover induced in this case by an increase in hybridization [13].…”

Section: Numerical Solutionmentioning

confidence: 91%

“…First, the enhancement of superconductivity by antisymmetric hybridization which had already been noticed [13]. Second, the combined behavior of the chemical potential decreasing γ and the concomitant increase in∆ ab is a clear signature of a BCS-BEC crossover induced in this case by an increase in hybridization [13]. Finally, notice the discontinuous behavior ofμ and∆ ab forγ ≈ 0.65, due to a topological phase transition associated with the appearance of gapless modes in the spectrum of excitations for this value ofγ.…”

Section: Numerical Solutionmentioning

confidence: 96%

“…These zero energy modes are associated with topological transitions in the system [13,31] as we will see further on in the text. Finally, the excitation energies are given by,…”

Section: A Excitation Energiesmentioning

confidence: 96%

“…We show it has non-trivial effects in the superconducting properties. We demonstrate that antisymmetric hybridization can enhance superconductivity [13] in multi-band systems. We also show that it can promote a crossover from a weak coupling, Bardeen, Cooper and Schrieffer (BCS) [14] type of superconductivity to a strong coupling one associated with a BoseEinstein condensation (BEC) of pairs [8,9].…”

Section: Introductionmentioning

confidence: 97%

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