PerspectivePhysics

Opening the gate on superconductivity

See allHide authors and affiliations

Science  11 Dec 2015:
Vol. 350, Issue 6266, pp. 1316-1317
DOI: 10.1126/science.aad7086

You are currently viewing the summary.

View Full Text

Summary

The deleterious effect of the magnetic field on superconductivity has plagued researchers and engineers alike for more than a century (1). Quantized vortices appear in most superconductors when applying a magnetic field and move under a current, creating dissipation that destroys the superconducting state. By pinning their motion through complex materials engineering, powerful magnets can be built for use in resonance imaging for medicine or to levitate trains. However, the magnetic field also perturbs superconductivity through the electron's magnetic property (known as spin). Superconductivity requires electrons to form Cooper pairs, in which the spins point oppositely to form a singlet state. Lu et al. (2) on page 1353 of this issue and another recent study (3) show that two-dimensional (2D) superconductors such as MoS2 can circumvent the negative effects of the magnetic field on Cooper pairs' spin. To induce superconductivity in MoS2, a transistor with two gates was used—a solid-state gate and a liquid gate—where moving ions generate a highly inhomogeneous electric field on top of thin MoS2 flakes. The resulting superconductor is extremely thin, just one MoS2 layer thick, and is remarkably robust to parallel magnetic fields. Although there are other thin superconductors robust to parallel magnetic fields, the mechanism providing insensitivity to the magnetic field is a new advance.