Kinetic approach to superconductivity hidden behind a competing order

Abstract

Nonvolatile and reversible switching of superconductivity has been demonstrated with electric pulses.

Superconductivity emerging from a stripe charge order in IrTe2 nanoflakes

“…Even in this coexisting phase, two ordered phases are macroscopically separated 22,23 . Such a macroscopic phase separation is also suggested in the super-cooled case 32,33,35 . However, in IrTe 2 nanoflakes, the stripe phase completely covers the whole regions of the sample, as confirmed by the spatial mapping of Raman signal, taken at~70 K well below T s (Fig.…”

“…1e). For the temperature sweeps in both directions, we took a slow cooling rate of~0.5 K/min, in order to minimise inhomogeneous domain formation of the stripe-chargeordered and charge-disordered phases, found in rapid-cooled IrTe 2 crystals 32,33,35 . The temperature dependent ρ(T) follows a metallic temperature dependence with abrupt changes at T s,dn and T s,up , due to the first-order stripe ordering transition as found in bulk crystals 24,25 .…”

“…Instead, FS reconstruction to the socalled cross-layer two-dimensional (2D) state 30,31 occurs due to suppression of the density of states (DOS) in the planes of Ir-Ir dimers running across the vdW gaps. These aspects suggest that the relationship between the stripe and superconducting orders in IrTe 2 may differ significantly from those of other TMDCs, as indicated by recent discoveries on the superconductivity in quenched or thinned IrTe 2 crystals [32][33][34] . Here using Raman spectroscopy, scanning tunnelling microscopy, and transport property measurements, we found that the parent stripe phase encompasses the whole superconducting dome in the thicknessdependent phase diagram (Fig.…”

Examining the surface phase diagram of IrTe2 with photoemission

“…Furthermore, we have identified a particular surface state that shifts in binding energy across the phase transitions, an observation confirmed by DFT calculations demonstrating that this surface-state binding energy is a function of the Ir dimer length. Our results therefore establish a solid basis for further photoemission studies of IrTe 2 under more exotic conditions like temperature quenching [15] or time-resolved studies, or using thin samples [14] and, ultimately, a monolayer of IrTe 2 . Figure 5 allows us to distinguish the evolution of the electronic structure of IrTe 2 and, in particular, of its surface state, as a function of temperature.…”

“…In this context, the surface of IrTe 2 offers an exciting platform for studying ordered phases in a quasi-2D material with large spin-orbit coupling on the transition metal site. A complex succession of chargeordered phases involving the creation of Ir dimers [11][12][13] has been observed in IrTe 2 at low temperature, which gives way to superconductivity for thin samples [14], after rapid cooling [15], or with Pt substitution [7].…”