Van der Waals coupling is emerging as a powerful method to engineer physical properties of atomically thin two-dimensional materials. In coupled graphene-graphene and graphene-boron nitride layers, interesting physical phenomena ranging from Fermi velocity renormalization to Hofstadter's butterfly pattern have been demonstrated. Atomically thin transition metal dichalcogenides, another family o...

Characterizing and controlling the interlayer orientations and stacking orders of two-dimensional (2D) bilayer crystals and van der Waals (vdW) heterostructures is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) crystals that result from different layer stackings provide an ideal platform to study the stacking configurat...

We have studied the fractional and integer quantum Hall effect in high mobility double layer 2D hole gas systems. The large hole effective mass inhibits tunneling, allowing us to investigate the regime in which the interlayer and intralayer interactions are comparable without significant interlayer tunneling occurring. As the interlayer separation is reduced we observe the formation of bilayer ...

van der Waals (vdW) forces, despite being relatively weak, hold the layers together in transition metal dichalcogenides (TMDs) and play a key role in their band structure evolution, hence profoundly affecting their physical properties. In this work, we experimentally probe the vdW interactions in MoS2 and other TMDs by measuring the valence band maximum (VBM) splitting (Δ) at K point as a funct...

The sensitivity of 1-3 piezocomposites can be improved by the addition of a third phase or interlayer around the piezoceramic rods which results in a composite with 1-1-3 connectivity. In the current investigation, dynamic surface displacements of both 1-3 and 1-1-3 piezocomposites were measured using a laser Doppler heterodyne interferometer. Dynamic displacement profiles showing the nonunifor...

This paper considers a system of two parallel quantum Hall layers with total filling factor 0 or 1. When the distance between the layers is small enough, electrons and holes in opposite layers form interlayer excitons, which have a finite effective mass and interact via a dipole-dipole potential. I present results for the chemical potential μ of the resulting bosonic system as a function of the...

Tunneling and Coulomb drag are sensitive probes of spontaneous interlayer phase coherence in bilayer two-dimensional electron systems at total Landau level filling factor nT=1. We find that the phase boundary between the interlayer phase coherent state and the weakly coupled compressible phase moves to larger layer separations as the electron density distribution in the bilayer is imbalanced. T...

Considerable progress has been made over the last decade in understanding the phenomenological properties of the cuprate high-Tc superconductors and in producing well characterized high quality materials. Nevertheless, the pairing mechanism itself remains controversial. We establish a criterion to test theories for layered superconductors relying on a substantial interlayer contribution. The cr...

Introduction: During a nano-mineralogy investigation of the Murchison CM2 meteorite, a new chromium sulfide mineral, Cr5S6, was identified as inclusions in two isolated olivine grains. High-resolution SEM, electron-backscatter diffraction (EBSD) and electron microprobe analyses have been used to characterize its composition and structure. The phase is known from laboratory studies of the Cr-S s...

Two commercial vermiculites from China and Libby were treated with different alcohols (methanol, ethanol, propanol butanol) at room temperature for up to one month afterwards irradiated microwaves. The exfoliated non-exfoliated particles characterized by X-ray diffraction, high-resolution transmission microscopy, thermal gravimetric analyses infrared spectroscopy explain the inconsistencies in ...