Volume 6 Issue 3, March 2023

By selectively engineering the surface roughness of micro-light-emitting-diode chips, and thus the strength of the van der Waals forces that bond them to a substrate, large-area displays can be created via a fluidic-assisted transfer method.

This Review examines the development of cryogenic memory technologies—including non-superconducting memories, superconducting memories and hybrid memories—and their potential application in superconducting single-flux quantum circuits and quantum computers.

Magnetic hysteresis in multiferroic heterostructures formed from the two-dimensional magnetic insulator chromium germanium telluride and a thin ferroelectric polymer can be electrically controlled with voltages of around 5 V.

An organogel that is based on poly(vinyl alcohol)–sodium borate and contains a percolating conductive network of silver particles and liquid metal microdroplets exhibits spontaneous mechanical and electrical self-healing, as well as an electrical conductivity of 7 × 10⁴ S m⁻¹.

By engineering the upper and lower surfaces of micro-light-emitting-diode chips to have different van der Waals forces, hundreds and thousands of chips can be accurately aligned on substrates and used to create active-matrix displays.

Magnetic meta-atoms made from lanthanum-doped barium hexaferrite can be used to create self-biased non-reciprocal metasurfaces capable of unidirectional transmission, non-reciprocal beam steering, non-reciprocal beam focusing and non-reciprocal holography.

Low-loss superconducting aluminium cables and on-chip impedance transformers can be used to link qubit modules and create superconducting quantum computing networks with high-fidelity intermodule state transfer.

Wireless ingestible microdevices can be tracked through the gastrointestinal tract of large animals in real time and with millimetre-scale spatial resolution by generating three-dimensional magnetic field gradients in the gastrointestinal field-of-view using high-efficiency planar electromagnetic coils, which encode each spatial point with a distinct magnetic field magnitude.

Micro-light-emitting-diode display applications are growing quickly as technology companies begin to use them in a range of products. Key to the development of these applications was the miniaturization of gallium nitride light-emitting diodes. Hongxing Jiang and Jingyu Lin recount how this was achieved.