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Two superconductors coupled by a weak link support an equilibrium Josephson electrical current which depends on the phase difference $varphi$ between the superconducting condensates [1]. Yet, when a temperature gradient is imposed across the junction, the Josephson effect manifests itself through a coherent component of the heat current that flows oppositely to the thermal gradient for $ varphi <pi/2$ [2-4]. The direction of both the Josephson charge and heat currents can be inverted by adding a $pi$ shift to $varphi$. In the static electrical case, this effect was obtained in a few systems, e.g. via a ferromagnetic coupling [5,6] or a non-equilibrium distribution in the weak link [7]. These structures opened new possibilities for superconducting quantum logic [6,8] and ultralow power superconducting computers [9]. Here, we report the first experimental realization of a thermal Josephson junction whose phase bias can be controlled from $0$ to $pi$. This is obtained thanks to a superconducting quantum interferometer that allows to fully control the direction of the coherent energy transfer through the junction [10]. This possibility, joined to the completely superconducting nature of our system, provides temperature modulations with unprecedented amplitude of $sim$ 100 mK and transfer coefficients exceeding 1 K per flux quantum at 25 mK. Then, this quantum structure represents a fundamental step towards the realization of caloritronic logic components, such as thermal transistors, switches and memory devices [10,11]. These elements, combined with heat interferometers [3,4,12] and diodes [13,14], would complete the thermal conversion of the most important phase-coherent electronic devices and benefit cryogenic microcircuits requiring energy management, such as quantum computing architectures and radiation sensors.
Recently Baselmans et al. [Nature, 397, 43 (1999)] showed that the direction of the supercurrent in a superconductor/normal/superconductor Josephson junction can be reversed by applying, perpendicularly to the supercurrent, a sufficiently large contr
We propose a setup for the experimental realization of unexpected and anisotropic $0$-$pi$ transitions of the Josephson current, in a junction whose link is made of irradiated Weyl semi-metal (WSM), due to the presence of chiral nodes. We show using
Superconductivity and ferromagnetism are antagonistic forms of order, and rarely coexist. Many interesting new phenomena occur, however, in hybrid superconducting/ferromagnetic systems. For example, a Josephson junction containing a ferromagnetic mat
The Josephson effect describes supercurrent flowing through a junction connecting two superconducting leads by a thin barrier [1]. This current is driven by a superconducting phase difference $phi$ between the leads. In the presence of chiral and tim
Topological superconductors can support localized Majorana states at their boundaries. These quasi-particle excitations have non-Abelian statistics that can be used to encode and manipulate quantum information in a topologically protected manner. Whi