Molecular Order Induced Charge Transfer in a C-Topological Insulator Moiré Heterostructure.

We synthesized and spectroscopically investigated monolayer (ML) C on the topological insulator (TI) BiTe. This C/BiTe heterostructure is characterized by an excellent translational order in a novel (4 × 4) C superstructure on a (9 × 9) cell of BiTe. Angle-resolved photoemission spectroscopy (ARPES) of C/BiTe reveals that ML C accepts electrons from the TI at room temperature, but no charge transfer occurs at low temperatures.

In-Plane Anisotropy of Electrical Transport in YTbBaCuO Films.

We fabricated high-quality c-axis-oriented epitaxial YBaCuO films with 15% of the yttrium atoms replaced by terbium (YTBCO) and studied their electrical properties. The Tb substitution reduced the charge carrier density, resulting in increased resistivity and decreased critical current density compared to pure YBaCuO films. The electrical properties of the YTBCO films showed an in-plane anisotropy in both the superconducting and normal states that, together with the XRD data, provided evidence for, at least, a partially twin-free film.

Phase-Selective Epitaxy of Trigonal and Orthorhombic Bismuth Thin Films on Si (111).

Over the past three decades, the growth of Bi thin films has been extensively explored due to their potential applications in various fields such as thermoelectrics, ferroelectrics, and recently for topological and neuromorphic applications, too. Despite significant research efforts in these areas, achieving reliable and controllable growth of high-quality Bi thin-film allotropes has remained a challenge. Previous studies have reported the growth of trigonal and orthorhombic phases on various substrates yielding low-quality epilayers characterized by surface morphology.

Aharonov-Bohm Interference and Phase-Coherent Surface-State Transport in Topological Insulator Rings.

We present low-temperature magnetotransport measurements on selectively grown SbTe-based topological insulator ring structures. These devices display clear Aharonov-Bohm oscillations in the conductance originating from phase-coherent transport around the ring. The temperature dependence of the oscillation amplitude indicates that the Aharonov-Bohm oscillations originate from ballistic transport along the ring arms.

Selective Area Epitaxy of Quasi-1-Dimensional Topological Nanostructures and Networks.

Quasi-one-dimensional (1D) topological insulators hold the potential of forming the basis of novel devices in spintronics and quantum computing. While exposure to ambient conditions and conventional fabrication processes are an obstacle to their technological integration, ultra-high vacuum lithography techniques, such as selective area epitaxy (SAE), provide all the necessary ingredients for their refinement into scalable device architectures. In this work, high-quality SAE of quasi-1D topological insulators on templated Si substrates is demonstrated.