Colloidal crystals are ordered arrays of particles that can exhibit a variety of interesting optical properties, such as iridescence and Bragg reflection. The symmetry of a colloidal crystal is determined by the arrangement of the particles, and it can have a significant impact on the crystal's properties. For example, crystals with a high degree of symmetry are typically more iridescent than those with a low degree of symmetry.

Breaking the symmetry of a colloidal crystal can be a challenge, but it can also lead to the creation of new and interesting materials. A recent study has revealed a new way to break symmetry in colloidal crystals by using a combination of electric fields and magnetic fields.

The study, which was conducted by researchers at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory, found that by applying an electric field and a magnetic field to a colloidal crystal, it is possible to induce the particles to form new, ordered structures. These new structures have a lower degree of symmetry than the original crystal, and they exhibit a number of interesting optical properties, such as enhanced iridescence and Bragg reflection.

The researchers believe that their new method could be used to create a variety of new materials with unique optical properties. These materials could have applications in a variety of fields, such as optics, photonics, and sensing.

The study was published in the journal Nature Materials.