In a paper published in National Science Review, an international team of scientists reports dramatic, reversible p-n switching during the semiconductor-to-semiconductor phase transition of BiI₃ under pressure. They propose a novel method for determining carrier polarity based on the self-driven photocurrent dominated by the photothermoelectric effect. The study further reveals the correlation between the switching of positive and negative photoconductivity and the carrier type under high pressure.

Growing cells in the laboratory is an art that humans have mastered decades ago. Recreating entire three-dimensional tissues is much more challenging. Empa researchers are developing a new hydrogel-based material that makes it possible to engineer artificial skin tissues, which can serve as living three-dimensional models of human skin for better understanding and treating skin diseases.

Novel physical effects based on chiral structural materials or materials with chiral interactions are being discovered and are becoming the cornerstone for constructing new spintronic devices. A Recent collaborative study published in Science Bulletin discovered a new way to deliberately control spin orientation in a more sophisticated manner. The approach enables the engineered ‘smart’ material, an oxide heterostructure of SrRuO₃-SrTiO₃, to decide when to halt its spin rotation.

In a breakthrough that brings nanoscience one step closer to precise control of chemical reactions, a team of researchers from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences (CAS) has consecutively removed the innermost atom and the outermost electron of a gold nanoparticle—without disturbing its overall structure. This precise manipulation allowed them to probe how the magnetic spin of the material influences its catalytic activity.

Diamonds with certain optically active defects can be used as highly sensitive sensors or qubits for quantum computers, where the quantum information is stored in the electron spin state of these colour centres. However, the spin states have to be read out optically, which is often experimentally complex. Now, a team at HZB has developed an elegant method using a photo voltage to detect the individual and local spin states of these defects. This could lead to a much more compact design of quantum sensors.

3D-printed hydrogel is soft, and sometimes it can be tough. However, could it be hard?

Here, researchers from Zhejiang University report a 3D photo-printable hard/soft switchable hydrogel composite, enabled by the phase transition (liquid/solid transition) of supercooled hydrated salt solution (solvent) within the hydrogel. This work suggests a bright future for the direct use of hard hydrogel as a robust industrial material.