Critical Buckling for the Disappearance of Superconductivity in Rare-Earth-DopedLa2−xSrxCu

Abstract

Analysis of the structural, transport, and superconducting properties of Nd-doped La2 "Sr Cu04 reveals a critical tilt angle of the Cu06 octahedra for the disappearance of superconductivity in the low temperature tetragonal phase. Our results indicate a strong inAuence of the tilt of the Cu06 octahedra on the electronic properties, suggesting the importance of spin-orbit coupling for the destruction of superconductivity and for the stabilization of a magnetic state.

Stripe order in superconducting La2−xBaxCuOHücker1, Zimmermann2, Gu3 et al. 2011Phys. Rev. B304434112View full textAdd to dashboardCite

“…3(a) we show, for all x, the temperature dependence of the orthorhombic strain T HT . 30 Both quantities show a monotonic decrease with increasing x, as shown in the inset to Fig. 3(a) and in Fig.…”

“…For La 2−x−y Nd y Sr x CuO 4 a critical tilt angle of 3.6 • has been identified to mark a phase boundary between SC and non-SC in the LTT phase. 30 This boundary is not very sharp and there are no reports yet on how deep charge stripe order persists into the SC LTT region with Φ < 3.6 • . The existence of such a critical angle is reasonable, since the symmetry breaking potential of the LTT phase should scale with Φ.…”

“…The substituion of La 3+ with the smaller Nd 3+ causes T c to go down even in the LTO phase, most likely as a consequence of the larger Φ. 30,81,84 For comparison, in La 2−x Ba x CuO 4 T HT and the corresponding Φ at low T are even smaller than in Nd-free La 2−x Sr x CuO 4 . The stronger suppression of the bulk SC in the Nd-doped system also corresponds with a broader range of x over which stripe order is detectable.…”

“…Among the debated interpretations is the so-called stripe model in which the charge carriers in the CuO 2 planes segregate into hole rich stripes, thus forming antiphase boundaries between intermediate spin stripes with locally AF correlations. 12,[26][27][28] In the LTT phase, which breaks the fourfold rotational symmetry of the individual CuO 2 planes, the electron-lattice coupling is believed to play a central role in the pinning of stripes, [29][30][31][32][33] although recent experiments under pressure revealed that stripes can break the symmetry even in the absence of long range LTT order. 34 So far, La 1.6−x Nd 0.4 Sr x CuO 4 is the only system with stripe-ordered LTT phase where magnetic and charge order have been studied with diffraction on both sides of x = 1/8.…”

Understanding the role of the local structure in the second order stuctural phase transition of La{sub 2-x}A{sub x}CuO{sub 4} (A = Ba,Sr)

“…This may be related to the fact that in this material the direction of the collective octahedral tilts which exist is [11OJ (the so-called LTT-phase) rather than [loo] (the LTO phase) as in all the well superconducting variants [1,3]. It has been suggested that in the LTT phase, a critical buckling angle for the tilts destroys superconductivity [4], possibly-due to spin-lattice coup may also be a relationship of the tilt direction to the mobility of charge stripes which have been seen in related 214 materials [6].…”