Bulk odd-frequency pairing in the superconducting Su-Schrieffer-Heeger model

The bulk-boundary correspondence in one dimension asserts that the physical quantities defined in the bulk and at the edge are connected, as well established in the argument for electric polarization. Recently, a spectral bulk-boundary correspondence (SBBC), an extended version of the conventional bulk-boundary correspondence to energy-dependent spectral functions, such as Green's functions, has been proposed in chiral symmetric systems, in which the chiral operator anticommutes with the Hamiltonian. In this study, we extend the SBBC to a system with impurity scattering and dynamical self-energies, regardless of the presence or absence of a gap in the energy spectrum. Moreover, the SBBC is observed to hold even in a system without chiral symmetry, which substantially generalizes its concept. The SBBC is demonstrated with concrete models, such as superconducting nanowires and a normal metallic chain. Its potential applications and certain remaining issues are also discussed.

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“…From the SBBC with z = iω n , F (iω n ) is related to an odd-frequency charge density wave as follows [35]:…”

Section: Rashba Nanowirementioning

confidence: 99%

Generalization of spectral bulk-boundary correspondence

2021

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“…The necessary broken translational symmetry has been achieved in junctions, [60][61][62][63][64][65][66][67][68][69][70][71][72] in the presence of impurities, [73][74][75][76][77] and also in models with a staggered lattice structure. [78][79][80] Bulk odd-frequency correlations are also pre-dicted to be present in multiband superconductors even without broken translational symmetry. 59,[81][82][83][84][85][86] But, the thermodynamic stability 87 of odd-frequency superconductivity has been questioned due to a most often found paramagnetic, or negative, Meissner response.…”

Section: Introductionmentioning

confidence: 99%

Odd-frequency pair density wave correlations in underdoped cuprates

Chakraborty,

Black-Schaffer

2020

Preprint

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Pair density waves, identified by Cooper pairs with finite center-of-mass momentum, have recently been observed in copper oxide based high Tc superconductors (cuprates). A charge density modulation or wave is also ubiquitously found in underdoped cuprates. Within a general mean-field one-band model we show that the coexistence of charge density waves and superconductivity in d-wave superconductors like cuprates, generates an odd-frequency spin-singlet pair density wave, in addition to the even-frequency counterparts. The strength of the induced odd-frequency pair density wave depends on the modulation wave vector of the charge density wave, with the odd-frequency pair density waves even becoming comparable to the even-frequency ones in parts of the Brillouin zone. The odd-frequency component of the pair density waves also gets enhanced when the charge density wave is uni-axial. Such a coexistence of superconductivity and uni-axial charge density wave has already been experimentally verified at high magnetic fields in underdoped cuprates. We further discuss the possibility of an odd-frequency spin-triplet pair density wave generated in the coexistence regime of superconductivity and spin density waves, applicable to the iron-based superconductors. Our work thus presents a route to bulk odd-frequency superconductivity in high Tc superconductors.

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“…In contrast, other mechanisms, such as spin, charge, or current fluctuations, may be favorable [6][7][8]. Disordered systems [9,10], heavy fermion compounds [11][12][13][14][15], topological materials [16][17][18], and multiband superconductors [19][20][21][22] have been suggested to host odd-ω pairs in the equilibrium situation. Alternatively, odd-ω pairs can also appear in driven conventional superconductors, where time translation symmetry is broken [23].…”

Section: Introductionmentioning

confidence: 99%

Signatures of odd-frequency pairing in the Josephson junction current noise

Souto,

Kuzmanovski,

Balatsky

2020

Preprint

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Odd frequency (odd-ω) electron pair correlations naturally appear at the interface between BCS superconductors and other materials. The detection of odd-ω pairs, which are necessarily nonlocal in time, is still an open problem. The main reason is that they do not contribute to static measurements described by time-local correlation functions. Therefore, dynamical measurements, which depend on non-local time correlations, are suitable for detecting these pairs. In this work, we study the signatures of odd-ω pairs in the supercurrent noise through a weak link between two superconductors at different superconducting phases. We show that the finite frequency current noise can be decomposed into three different contributions coming from even frequency (even-ω), odd-ω pair amplitudes, and electron-hole correlation functions. Odd-ω pairing, which is inter-lead (between electrons at different sides of the junction), provides a positive contribution to the noise, becoming maximal at a superconducting phase difference of π. In contrast, intra-lead even-ω pair amplitude tends to reduce the noise, except for a region close to π, controlled by the transmission of the junction.

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Bulk odd-frequency pairing in the superconducting Su-Schrieffer-Heeger model

Cited by 12 publications

References 72 publications

Generalization of spectral bulk-boundary correspondence

Generalization of spectral bulk-boundary correspondence

Odd-frequency pair density wave correlations in underdoped cuprates

Signatures of odd-frequency pairing in the Josephson junction current noise

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