Highly Anisotropic Mechanical Response of the Van der Waals Magnet CrPS₄

Semiconducting van der Waals magnets exhibit a rich physical phenomenology with different collective excitations, as magnons or excitons, that can be coupled, thereby offering new opportunities for optoelectronic, spintronic, and magnonic devices. In contrast with the well-studied van der Waals magnets CrI₃ or Fe₃GeTe...

Nanomechanical absorption spectroscopy of 2D materials with femtowatt sensitivity

Nanomechanical spectroscopy (NMS) is a recently developed approach to determine optical absorption spectra of nanoscale materials via mechanical measurements. It is based on measuring changes in the resonance frequency of a membrane resonator vs. the photon energy of incoming light. This method is a direct measurement of absorption, which has...

Ultrathin Piezoelectric Resonators Based on Graphene and Free-Standing Single-Crystal BaTiO₃

Suspended piezoelectric thin films are key elements enabling high-frequency filtering in telecommunication devices. To meet the requirements of next-generation electronics, it is essential to reduce device thickness for reaching higher resonance frequencies. Here, the high-quality mechanical and electrical properties of graphene electrodes...

Tunable Photodetectors via In Situ Thermal Conversion of TiS₃ to TiO₂

In two-dimensional materials research, oxidation is usually considered as a common source for the degradation of electronic and optoelectronic devices or even device failure. However, in some cases a controlled oxidation can open the possibility to widely tune the band structure of 2D materials. In particular, we demonstrate the controlled...

High-frequency stochastic switching of graphene resonators near room temperature

Stochastic switching between the two bistable states of a strongly driven mechanical resonator enables detection of weak signals based on probability distributions, in a manner that mimics biological systems. However, conventional silicon resonators at the microscale require a large amount of fluctuation power to achieve a switching rate in the...

Thickness-Dependent Refractive Index of 1L, 2L, and 3L MoS ₂ , MoSe ₂ , WS ₂ , and WSe ₂

An interesting aspect of 2D materials is the change of their electronic structure with the reduction of thickness. Molybdenum and tungsten-based transition metal dichalcogenides form an important family of 2D materials, whose members show a thickness-dependent bandgap and strong light–matter interaction. In this work, the experimental...

Highly anisotropic mechanical and optical properties of 2D layered As₂S₃ membranes

Two-dimensional (2D) materials with strong in-plane anisotropy are of interest for enabling orientation-dependent, frequency-tunable, optomechanical devices. However, black phosphorus (bP), the 2D material with the largest anisotropy to date, is unstable as it degrades in air. In this work we show that As₂S₃ is an...

High Current Density Electrical Breakdown of TiS₃ Nanoribbon-Based Field-Effect Transistors

The high field transport characteristics of nanostructured transistors based on layered materials are not only important from a device physics perspective but also for possible applications in next generation electronics. With the growing promise of layered materials as replacements to conventional silicon technology, the high current density...