Majorana STM as a perfect detector of odd-frequency superconductivity

We consider normal-superconductor (NS) and superconductor-normal-superconductor (SNS) junctions based on one-dimensional nanowires with Rashba spin-orbit coupling and proximityinduced s-wave spin-singlet superconductivity and analytically demonstrate how both even-and odd-frequency and spin-singlet and -triplet superconducting pair correlations are always present. In particular, by using a fully quantum mechanical scattering approach, we show that Andreev reflection induces mixing of spatial parities at interfaces, thus being the unique process which generates odd-frequency pairing; on the other hand, both Andreev and normal reflections contribute to even-frequency pairing. We further find that locally neither odd-frequency nor spin-triplet correlations are induced, but only even-frequency spin-singlet pairing. In the superconducting regions of NS junctions, the interface-induced amplitudes decay into the bulk, with the odd-frequency components being generally much larger than the even-frequency components at low frequencies. The odd-frequency pairing also develops short and long-period oscillations due to the chemical potential and spin-orbit coupling, respectively, leading to a visible beating feature in their magnitudes. Moreover, we find that in short SNS junctions at π-phase difference and strong spin-orbit coupling, the odd-frequency spin-singlet and -triplet correlations strongly dominate with an alternating spatial pattern for a large range of sub-gap frequencies.arXiv:1805.07948v2 [cond-mat.mes-hall]

Section: Introductionmentioning

confidence: 99%

Odd-frequency superconducting pairing in junctions with Rashba spin-orbit coupling

Cayao

Black‐Schaffer

2018

“…[42] and [43] for recent reviews on experiments and theory, respectively. In particular, there are investigations of the Josephson effect through quantum dots [44][45][46][47][48][49], multiple Andreev reflections [50][51][52][53][54][55], the interplay between superconducting correlations and the Kondo effect [56][57][58][59][60][61], the generation of unconventional superconducting correlations in quantum dots [62][63][64][65], Cooper pair splitting [66][67][68][69][70][71] and the generation of Majorana fermions [72][73][74][75]. Thermoelectric effects in superconductor-quantum dot hybrids have been studied in the absence of Coulomb interactions [76].…”

Section: Introductionmentioning

confidence: 99%

Phase-dependent heat and charge transport through superconductor–quantum dot hybrids

Kamp

Sothmann

2019

Self Cite

We analyze heat and charge transport through a single-level quantum dot coupled to two BCS superconductors at different temperatures to first order in the tunnel coupling. In order to describe the system theoretically, we extend a real-time diagrammatic technique that allows us to capture the interplay between superconducting correlations, strong Coulomb interactions and nonequilibrium physics. We find that a thermoelectric effect can arise due to the superconducting proximity effect on the dot. In the nonlinear regime, the thermoelectric current can also flow at the particle-hole symmetric point due to a level renormalization caused by virtual tunneling between the dot and the leads. The heat current through the quantum dot is sensitive to the superconducting phase difference. In the nonlinear regime, the system can act as a thermal diode. arXiv:1809.09428v3 [cond-mat.mes-hall]

“…It has been also shown that the anomalous proximity effect can occur in topologically designed hybrid systems based on conventional spin-singlet s-wave superconductor systems with spin-orbit coupling and Zeeman effect [31,46,47] and the anomalous proximity effect has been studied considering the classifica-tion of the topological nature of the Hamiltonian [48]. In addition, there are several studies reporting that oddfrequency pairings appear as a Majorana fermion, which is a special type of the ZESABS in various topological superconducting systems [46,[49][50][51][52][53][54][55][56][57][58][59].…”

Section: Introductionmentioning

confidence: 99%

Theory of the proximity effect in two-dimensional unconventional superconductors with Rashba spin-orbit interaction

Tamura

Tanaka

2019

We study the anomalous proximity effect in diffusive normal metal (DN)/unconventional superconductor junctions, where the local density of states (LDOS) in the DN has a zero-energy peak due to the penetration of the odd-frequency spin-triplet s-wave pairing. In this study, we consider a two-dimensional unconventional superconductor on the substrate in the presence of a Rashba spinorbit coupling (RSOC) λ, where the Rashba vector is parallel to the z-direction. The anomalous proximity effect, originally predicted in spin-triplet p-wave superconductor junctions, is sensitive to the RSOC. It disappears with the increase of λ. On the other hand, the anomalous proximity effect can be switched on by the large λ values in the spin-singlet dxy-wave superconductor junctions. The resulting zero-energy LDOS and the magnitude of the odd-frequency spin-triplet s-wave pair amplitude increase with the increase of λ.