Stripe order enhanced superconductivity in the Hubbard model

Understand

Unidirectional ("stripe") charge-density-wave order has now been established as a ubiquitous feature in the phase diagram of the cuprate high temperature (HT) superconductors, where it generally competes with superconductivity (SC).

• None-the-less, on theoretical grounds it has been conjectured that stripe order (or other forms of "optimal" inhomogeneities) may play an essential positive role in the mechanism of HTSC.
• Here we report density matrix renormalization group studies of the Hubbard model on long 4 and 6 leg cylinders where the hopping matrix elements transverse to the long direction are periodically modulated - mimicing the effect of putative period-2 stripe order.
• We find even modest amplitude modulations can enhance the long-distance SC correlations by many orders of magnitude, and drive the system into a phase with a substantial spin gap and SC quasi-long-range-order with a Luttinger exponent, $K_{sc} \sim 1$.