Are Stripes a Universal Feature of High-Tc Superconductors?

As if the superconducting copper oxides weren't mysterious enough, experiments within the past decade have revealed a magnetic structure—at least in members of the lanthanum strontium copper oxide family—whose period is different from that of the underlying lattice. One explanation that has attracted increasing attention is the possibility that stripe phases may form spontaneously when experimenters dope these high critical‐temperature ${\mathrm{(T}}_c)$ materials. According to this postulate, the added charges line up in rows in the copper oxide plane, sandwiching between them regions of copper atoms whose spins are aligned antiferromagnetically, with nearest neighbors having opposite spins. The repeat pattern of these spin regions is generally different from that of the crystal lattice, thus explaining the incommensurate peaks seen in diffraction studies.