Highlights

The kagome lattice is an outstanding example of a frustrated magnet, a system in which the magnetic moments cannot satisfactorily align to minimize the energy. Its ground-state configuration has been a long-standing puzzle. Recent debate has focused on the relative stability of a valence bond-crystal, and an isotropic spin-liquid (where quantum fluctuations cause all ordering to disappear). Using numerical techniques, we have shown [1] that there is an intermediate competing

Solid-state devices rely on the control of the flow of electrons and holes at the interface (“heterojunction”) formed between different semiconductors. Silicon is the workhorse of the semiconductor industry. However, until now, creating a heterojunction between Si and other materials with a larger energy gap has been an intractable problem for the most part, because of the lack of a lattice match between Si and crystalline wide-gap materials. In this seed, Sturm, Kahn,  Schwartz and Loo report two materials that do

Electron paramagnetic resonance (EPR) is commonly used to manipulate and measure the magnetic moments (or spins) of electrons.  IRG-D researchers at the Princeton Center for Complex Materials (PCCM) have demonstrated a 100 fold improvement in sensitivity to the electrons’ spins by combining long-coherence donor electrons in isotopically enriched silicon with superconducting Nb microresonators.1  The PCCM researchers have previously shown that these donor impurities, each binding one electron, exhibit exceptionally

Block copolymer thin films are effective templates for fabricating large arrays of nanoscopic objects; for example, polymers which self-assemble into cylinders lying in the plane of the film yield striped patterns, which can be replicated in metal to yield nanowire grids which effectively polarize the short-wavelength ultraviolet light used in today’s advanced production photolithography.   But other applications demand more perfect order of the striped-pattern template:  perfectly straight and unbroken wires. 

Processed NW network

Fig. 1 Device schematic, optical micrograph, and initialization scheme.

Thin block copolymer films are highly relevant for many scientific and industrial applications due to their ability to form uniform domains of controllable shape at nanometer length scales. From a technological point of view, the cases of shapes with long axes may be of interest in the fabrication of nanowires, while upright cylinders and spheres could have potential applications in the patterning of hexagonal arrays for data storage.