Variation of the extended s-wave superconducting order parameter: From s-wave to g-wave

Abstract

We investigate evolution of properties of an extended s-wave superconductor, when the order parameter varies from an s-wave to a g-wave continuously, by using a model order parameter ∆(k) = ∆0((1−x)+x sin 4 θ cos 4φ). The evolution of the gap amplitude, the density of states, and the specific heat are mainly focused on. For x < 0.5, due to the existence of a finite sized gap, the characteristic behaviors more or less follow those of the s-wave. Sudden changes in the characteristic behaviors come out for x ≥ 0.5, due to appearances of nodes. For x = 0.5, point nodes in the order parameter on the Fermi surface appear, while for x > 0.5, line nodes appear. Although they are different kinds of nodes which would usually induce different power-law dependencies in superconducting properties, interestingly enough, they give rise to the same characteristic behavior. The detailed structure of the point nodes for x = 0.5 is investigated, and it is explained why they lead to the same dependence as the line nodes.

Nonsymmorphic cubic Dirac point and crossed nodal rings across the ferroelectric phase transition in LiOsO3

“…In the past decade, the study of topological phases of matter has become one of the most active areas of research in condensed matter physics [1][2][3][4]. Extending the earlier work on gapped topological phases, such as topological insulators [5][6][7][8][9][10][11][12][13][14][15][16] and topological superconductors [17][18][19][20][21][22][23][24][25][26][27], the focus has shifted recently to gapless phases, especially the so-called topological semimetals (TSMs) [28][29][30][31][32][33].…”

Signatures of surface Majorana modes in the magnetic response of topological superconductors

“…The localised and charge neutral character of Majorana modes has induced most of the theoretical detection proposals and the experimental efforts to focus on local spectroscopy, Josephson effect, and interferometry, to find a proof of their existence [32][33][34] . As far as class DIII topological superconductors is concerned, the presence of surface Majorana modes is expected to produce a strongly anisotropic spin susceptibility 35 .…”

Magnetic tilting and emergent Majorana spin connection in topological superconductors

“…Due to their charge neutrality and localized character, most of the theoretical proposals and the experimental efforts to detect Majorana states have focused on local spectroscopy, Josephson effect, and interferometry, as a proof of their existence 33,34 . Besides, surface Majorana modes are expected to produce a strong anisotropy in the spin suscepibility 35 .…”