# Synopsis: A quantum phase transition for a spin liquid

Researchers report an unusual critical scaling regime in a material that goes from a spin liquid to a spiral magnet upon application of a magnetic field.

Low-dimensional, geometrically frustrated quantum antiferromagnets can support a “spin liquid” state, which has no long-range order, even at very low temperatures, and with a finite energy gap. In some of these systems, a magnetic field can drive a quantum phase transition to an ordered phase that is mathematically equivalent to Bose-Einstein condensation or the Mott metal-insulator transition. This makes the study of criticality and dimensional crossover in spin liquids of wide significance.

In a Rapid Communication appearing in Physical Review B, Vasile Garlea and collaborators at the Oak Ridge National Laboratory, USA, the Hahn-Meitner Institut in Germany, and the Commissariat à l’Énergie Atomique in Grenoble, France, report an unusual magnetic-field-induced spin ordering in a geometrically frustrated quasi-one-dimensional compound, ${\text{Sul-Cu}}_{2}{\text{Cl}}_{4}$. At high magnetic fields, the spins order into a spiral that twists around the $c$ axis. This spiral, or “helimagnetic,” phase has a definite chirality—the spins spiral in one direction but not the other.

With neutron scattering, Garlea et al. extract critical exponents for the phase transition that do not conform to well-understood theoretical models. These results pose interesting questions regarding the role of chirality in determining the critical behavior of a phase transition from a spin liquid to an ordered magnet. – Sarma Kancharla

More Features »

### Announcements

More Announcements »

Magnetism

## Previous Synopsis

Interdisciplinary Physics

## Next Synopsis

Strongly Correlated Materials

## Related Articles

Condensed Matter Physics

### Synopsis: Revealing a Hidden Spin Polarization

Photoemission spectroscopy has detected two different populations of spin-polarized electrons that are “hidden” within a layered, graphene-like material. Read More »

Magnetism

### Focus: Electric Power from the Earth’s Magnetic Field

A loophole in a result from classical electromagnetism could allow a simple device on the Earth’s surface to generate a tiny electric current from the planet’s magnetic field. Read More »

Magnetism

### Viewpoint: Liquid Light with a Whirl

An elliptical light beam in a nonlinear optical medium pumped by “twisted light” can rotate like an electron around a magnetic field. Read More »