Related papers: Half-Integer Flux Quantization in Unconventional S…
The orbital component of the order parameter in the cuprate high-Tc cuprate superconductors is now well established, in large part because of phase sensitive tests. Although it would be desirable to use such tests on other unconventional…
The discovery of the new class of pnictide superconductors has engendered a controversy about their pairing symmetry, with proposals ranging from an extended s-wave or "s$_{\pm}$" symmetry to nodal or nodeless d-wave symmetry to still more…
We study the order parameter phase fluctuation effects in cuprate superconductors near T=0, using a quasi-two-dimensional d-wave BCS model. An effective phason theory is obtained which is used to estimate the strength of the fluctuations,…
Superconducting quantum circuits are promising systems for experiments testing fundamental quantum mechanics on a macroscopic scale and for applications in quantum information processing. We report on the fabrication and characterization of…
Engineering artificial systems by twisting and stacking van der Waals materials has proven to be an excellent platform for exploring emergent quantum phenomena that can be significantly different from the constituents. Recent advances in…
We present phase-sensitive evidence that the electron-doped cuprates Nd1.85Ce0.15CuO4-y (NCCO) and Pr1.85Ce0.15CuO4-y (PCCO) have d-wave pairing symmetry. This evidence was obtained by observing the half-flux quantum effect, using a…
Hybrid systems represent one of the frontiers in the study of unconventional superconductivity and are a promising platform to realize topological superconducting states. Owing to their mesoscopic dimensions, these materials are challenging…
The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control…
Two-dimensional Eliashberg equations have been solved by use of a mixed interaction with $s$- and $d$-channels. It is discussed what kind of pairing symmetry of the superconducting state can be realized when the channel mixing parameters…
We use a scanning superconducting quantum interference device (SQUID) to image the magnetic flux produced by a superconducting device designed for quantum computing. The nanometer-scale SQUID-on-tip probe reveals the flow of superconducting…
Phase-sensitive measurements on a composite ring made of a superconductor of interest connected by a known singlet $s$-wave superconductor can unambiguously determine its pairing symmetry. In composite rings with epitaxial $\beta-$Bi$_2$Pd…
Recent phase sensitive experiments on high Tc superconductors, e.g., YBa_2Cu_3O_7 single crystals, have established the d-wave nature of the cuprate materials. Here we discuss how to make use of d-wave Josephson junctions in the…
Since the discovery of high-temperature superconductivity in 1986 by Bednorz and Mueller, great efforts have been devoted to finding out how and why it works. From the d-wave symmetry of the order parameter, the importance of…
Although the microscopic origin of the superconductivity in high Tc copper oxides remains the subject of active inquiry, several of their electronic characteristics are well established as universal to all the known materials, forming the…
The phase-sensitive experiments on cuprate superconductors have told us about the symmetry of the condensate wavefunction. However, they can not determine the pairing symmetry of Cooper pairs. To describe a superconducting state, two…
Since the discovery of high-Tc cuprate superconductivity in 1986 many new experimental techniques and theoretical concepts have been developed. In particular it was shown that the BCS theory of d-wave superconductivity describes…
Superconductivity in the cuprates, discovered in the late 1980s and occurring at unprecedentedly high temperatures (up to about 140K) in about thirty chemically distinct families, continues to be a major problem in physics. In this article,…
Unconventional superconductors have been long sought for their potential applications in quantum technologies and devices. A key challenge impeding this effort is the difficulty associated with probing and characterizing candidate materials…
We revisit the pairing symmetry competition in quasi-one-dimensional systems. We show that spin-triplet s-wave pairing, where the pair is formed by electrons with different times and has an odd-frequency symmetry, can be realized in systems…
We show a novel method for controlling the coupling of flux-based qubits by means of a superconducting transformer with variable flux transfer function. The device is realized by inserting a small hysteretic dc SQUID with unshunted…