PhD student Syl Shaw and supervisor Rudo Roemer apply the real-space renormalisation group method to the Chalker–Coddington model of the quantum Hall transition. This approach provides a convenient numerical estimation of the localisation critical exponent, ν. Previous such studies found ν=2.39 which falls considerably short of the current best estimates by transfer matrix (2.593) and exact-diagonalisation studies (2.58). By increasing the amount of data 500 fold they can now measure closer to the critical point and find an improved estimate 2.51. This deviates only 3% from the previous two values and is already better than the 7% accuracy of the classical small-cell renormalisation approach from which their method is adapted.

Blending ordering within an uncorrelated disorder potential in families of 3D Lieb lattices preserves the macroscopic degeneracy of compact localized states and yields unconventional combinations of localized and delocalized phases—as shown in Liu et al. (Phys Rev B 106:214204, 2022). Danieli, Liu and Roemer proceed to reintroduce translation invariance in the system by further ordering the disorder, and discuss the spectral structure and eigenstates features of the resulting perturbed lattices. This strategy, herewith implemented in the 3D Lieb lattice, highlights order restoration as experimental pathway to engineer spectral and states features in disordered lattice structures in the pursuit of quantum storage and memory applications.

Two-dimensional random metal networks possess unique electrical and optical properties, such as almost total optical transparency and low sheet resistance. These properties are closely related to their disordered structure. In this work, Prof. Römer and colleagues from Dresden, Germany, give a detailed experimental and theoretical investigation of these plasmonic properties, revealing Anderson (disorder-driven) localized surface plasmon resonance. This could support the development of design rules for the underlying conduction networks, e.g., in order to further optimize design transparency for envisaged future applications as transparent electrodes.

Dr Samuel Seddon has recently published his paper in Physical Review B titled 'Ferroelastic control of magnetic domain structure: Direct imaging by magnetic force microscopy.'Link opens in a new window

A major new quantum technology research hub which is being led by researchers from University College London (UCL) and the University of Cambridge has been launched in collaboration with researchers from the University of Warwick.

Professor Reinhard MaurerLink opens in a new window has recently published his paper in Physical Review Letters titledStructure of graphene grown on Cu(111): X-ray Standing Wave Measurement and Density Functional Theory Prediction'Link opens in a new window