Realization of a two-dimensional Weyl semimetal and topological Fermi strings.

A two-dimensional (2D) Weyl semimetal, akin to a spinful variant of graphene, represents a topological matter characterized by Weyl fermion-like quasiparticles in low dimensions. The spinful linear band structure in two dimensions gives rise to distinctive topological properties, accompanied by the emergence of Fermi string edge states. We report the experimental realization of a 2D Weyl semimetal, bismuthene monolayer grown on SnS(Se) substrates.

Epitaxial Growth of Large-Scale 2D CrTe Films on Amorphous Silicon Wafers With Low Thermal Budget.

2D van der Waals (vdW) magnets open landmark horizons in the development of innovative spintronic device architectures. However, their fabrication with large scale poses challenges due to high synthesis temperatures (>500 °C) and difficulties in integrating them with standard complementary metal-oxide semiconductor (CMOS) technology on amorphous substrates such as silicon oxide (SiO) and silicon nitride (SiN). Here, a seeded growth technique for crystallizing CrTe films on amorphous SiN/Si and SiO/Si substrates with a low thermal budget is presented.

A Reconfigurable Tri-Mode Frequency-Locked Loop Readout Circuit for Biosensor Interfaces.

In this article, a frequency-locked loop (FLL) based multimodal readout integrated circuit (IC) for interfacing with off-chip temperature, electrochemical, and pH sensors is presented. By reconfiguring its switched-capacitor feedback network, the readout circuit is able to measure resistance, current, and voltage without additional active analog front-end circuits. A prototype IC was fabricated in a 0.

Wireless, Multi-Sensor System-on-Chip for pH and Amperometry Powered by Body Heat.

This article presents a body-heat-powered, multi-sensor SoC for measurement of chemical and biological sensors. Our approach combines analog front-end sensor interfaces for voltage- (V-to-I) and current-mode (potentiostat) sensors with a relaxation oscillator (RxO) readout scheme targeting << 10 μW power consumption. The design was implemented as a complete sensor readout system-on-chip, including a low-voltage energy harvester compatible with thermoelectric generation and a near-field wireless transmitter.

Observation of Gapped Topological Surface States and Isolated Surface Resonances in PdTe Ultrathin Films.

The superconductor PdTe is known to host bulk Dirac bands and topological surface states. The coexistence of superconductivity and topological surface states makes PdTe a promising platform for exploring topological superconductivity and Majorana bound states. In this work, we report the spectroscopic characterization of ultrathin PdTe films with thickness down to three monolayers (ML).

Realization of unpinned two-dimensional dirac states in antimony atomic layers.

Two-dimensional (2D) Dirac states with linear dispersion have been observed in graphene and on the surface of topological insulators. 2D Dirac states discovered so far are exclusively pinned at high-symmetry points of the Brillouin zone, for example, surface Dirac states at [Formula: see text] in topological insulators BiSe(Te) and Dirac cones at K and [Formula: see text] points in graphene. The low-energy dispersion of those Dirac states are isotropic due to the constraints of crystal symmetries.

Dirac Fermion Cloning, Moiré Flat Bands, and Magic Lattice Constants in Epitaxial Monolayer Graphene.

Tuning interactions between Dirac states in graphene has attracted enormous interest because it can modify the electronic spectrum of the 2D material, enhance electron correlations, and give rise to novel condensed-matter phases such as superconductors, Mott insulators, Wigner crystals, and quantum anomalous Hall insulators. Previous works predominantly focus on the flat band dispersion of coupled Dirac states from different twisted graphene layers. In this work, a new route to realizing flat band physics in monolayer graphene under a periodic modulation from substrates is proposed.

Thermodynamic constraints on the assembly and diversity of microbial ecosystems are different near to and far from equilibrium.

Non-equilibrium thermodynamics has long been an area of substantial interest to ecologists because most fundamental biological processes, such as protein synthesis and respiration, are inherently energy-consuming. However, most of this interest has focused on developing coarse ecosystem-level maximisation principles, providing little insight into underlying mechanisms that lead to such emergent constraints. Microbial communities are a natural system to decipher this mechanistic basis because their interactions in the form of substrate consumption, metabolite production, and cross-feeding can be described explicitly in thermodynamic terms.

The role of competition versus cooperation in microbial community coalescence.

New microbial communities often arise through the mixing of two or more separately assembled parent communities, a phenomenon that has been termed "community coalescence". Understanding how the interaction structures of complex parent communities determine the outcomes of coalescence events is an important challenge. While recent work has begun to elucidate the role of competition in coalescence, that of cooperation, a key interaction type commonly seen in microbial communities, is still largely unknown.

Giant Topological Hall Effect in van der Waals Heterostructures of CrTe/BiTe.

Discoveries of the interfacial topological Hall effect (THE) provide an ideal platform for exploring the physics arising from the interplay between topology and magnetism. The interfacial topological Hall effect is closely related to the Dzyaloshinskii-Moriya interaction (DMI) at an interface and topological spin textures. However, it is difficult to achieve a sizable THE in heterostructures due to the stringent constraints on the constituents of THE heterostructures, such as strong spin-orbit coupling (SOC).

Room-temperature intrinsic ferromagnetism in epitaxial CrTe ultrathin films.

While the discovery of two-dimensional (2D) magnets opens the door for fundamental physics and next-generation spintronics, it is technically challenging to achieve the room-temperature ferromagnetic (FM) order in a way compatible with potential device applications. Here, we report the growth and properties of single- and few-layer CrTe, a van der Waals (vdW) material, on bilayer graphene by molecular beam epitaxy (MBE). Intrinsic ferromagnetism with a Curie temperature (T) up to 300 K, an atomic magnetic moment of ~0.

Thermodynamics of switching in multistable non-equilibrium systems.

Multistable non-equilibrium systems are abundant outcomes of nonlinear dynamics with feedback, but still relatively little is known about what determines the stability of the steady states and their switching rates in terms of entropy and entropy production. Here, we will link fluctuation theorems for the entropy production along trajectories with the action obtainable from the Freidlin-Wentzell theorem to elucidate the thermodynamics of switching between states in the large volume limit of multistable systems. We find that the entropy production at steady state plays no role, but the entropy production during switching is key.