Physicists at Johannes Gutenberg University Mainz (JGU) and the Max Planck Institute for Polymer Research (MPI-P) in Mainz have discovered so-called "true stripes" in a trilayer metal oxide. The stripe phase observed by the research team led by Professor Jeroen van den Brink originates from purely electronic interactions and is not associated with any form of lattice distortion. This is a remarkable discovery that revises the current theoretical view on the subject. The "true stripes" were found in nickelates (nickel oxides), which are strongly correlated materials of growing technological importance. The research results have been published in the renowned scientific journal Nature Physics.

The stripe phase is a type of electronic ordering that spontaneously forms under certain conditions in strongly correlated materials. In these materials, the interaction between electrons is so strong that the electrons cannot be regarded as independent particles anymore. This leads to the emergence of complex electronic properties, such as colossal magnetoresistance and high-temperature superconductivity.

Stripes consist of alternating stripes of high and low electron density. They have been observed in several materials, including cuprates (copper oxides) and nickelates (nickel oxides). In most cases, the stripes are accompanied by a lattice distortion, which means that the crystal lattice of the material is also modulated. This lattice distortion is usually a result of the strong electron-phonon coupling in these materials.

In cuprates, the stripes were found to be pinned to a lattice modulation, leading to so-called "charge-lattice stripes". In some nickelates, however, stripes exist in the complete absence of lattice distortion, and are therefore referred to as "true stripes". Such true stripes are much less common and their microscopic origin is still poorly understood.

The discovery of true stripes by Jeroen van den Brink's research team in a trilayer nickelate is a significant advance in our understanding of these mysterious electronic phenomena. The researchers used a combination of theoretical modeling and advanced numerical simulations to identify the conditions under which true stripes form in this material.

The theoretical results reveal that the stripe phase originates from the interplay between strong electronic correlations and quantum fluctuations. Under specific conditions, these factors can give rise to a spontaneous electronic ordering, leading to the formation of true stripes.

The study of stripes and other electronic orders is crucial for understanding the physics of strongly correlated materials and for the development of novel functional devices based on these materials. The results obtained by the research team in Mainz provide important insights into the nature of true stripes and pave the way for further research in this emerging field of condensed matter physics.