Research Highlights for Thin Film Quantum Materials

Non-uniform magnetic domains with non-trivial topology, such as vortices and skyrmions, are proposed as superior state variables for nonvolatile information storage. So far, the possibility of logic operations using topological objects has not been considered. Here, we demonstrate numerically that the topology of the system plays a significant role for its dynamics, using the example of vortex-antivortex pairs in a planar ferromagnetic film. Utilising the dynamical properties and geometrical confinement, direct logic communication between the topological memory carriers is realised.

The breaking of time reversal symmetry (TRS) in three-dimensional (3D) topological insulators (TIs), and thus the opening of a ‘Dirac-mass gap’ in the linearly dispersed Dirac surface state, is a prerequisite for unlocking exotic physical states. Introducing ferromagnetic long-range order by transition metal doping has been shown to break TRS. Here, we present the study of lanthanide (Ln) doped Bi2Te3, where the magnetic doping with high-moment lanthanides promises large energy gaps.

The merit of advanced hybrid memory and logic devices not only lies in their high performance and superior functionalities but also their capability to establish a complete computational system, including full memory and logic functionalities. In this paper, a novel, ultrahigh-performance device concept for hybrid memory and logic applications is presented, which relies on spin-based magnetic Hall measurements. Employing a pair of spintronic heterostructures, the new system shows flexible functionality as both a robust memory element and a complex logic device.

The tremendous potential of topological insulators (TIs) for applications in the next generation of device technology has been recognised for some years, due to their superior conductivity and spin selectivity, but finding a way to employ their exciting properties has thus far been difficult. With results recently published in the journal Scientific Reports, researchers working at Diamond Light Source have demonstrated that TIs can be used to separate the spin and charge information carried by electrons, opening up the potential for ultra-fast, energy efficient spintronics devices.

Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme.

We present the catalyst-free growth of binary Bi2Te3 topological insulator nanostructures on c-plane sapphire substrates by molecular beam epitaxy. Dense arrays of single-crystalline nanostructures, growing along the [110] direction, are obtained for substrate temperatures ranging from ∼180 °C to 260 °C. The growth rate and shape of the nanostructures are highly temperature-dependent. The microscopic study of the nanostructures and their relationship to the underlying Bi2Te3 thin film gives an insight into the growth mechanism.