Search

On April 8, 2017, PCCM held its first Día de la Ciencia at the Princeton Public Library. Forty scientists, mostly PCCM members, at 20 tables, met with over 500 members of the community.

Semiconductors with narrow energy gaps have electronic properties, including a high mobility and strong spin-orbit coupling, that are advantageous for electronic device applications. The switching speed of a field-effect transistor and the sensitivity of a geometrical magnetoresistor are improved by a high carrier mobility. In addition to these traditional devices, we are studying devices that take advantage of quantum-mechanical or spin-orbit effects.

Surface plasmons - collective oscillations of free charges - on metal surfaces have resulted in demonstrations of enhanced optical transmission, collimation of light through a subwavelength aperture, negative permeability and refraction at visible wavelengths, and second-harmonic generation. The structures that display these plasmonic phenomena typically consist of ordered arrays of particles or holes with sizes of the order of 100 nm.

Rather than the typical approach of exfoliating and peeling off individual atomic layers to make a 2D material, the researchers grew the 2D material inside of another matrix. The work has dubbed this new class of materials "endotaxial" from the Greek roots "endo", meaning within, and "taxis", meaning in an ordered manner.

Soft materials known as molecular bottlebrush block polymers comprise a polymer backbone with densely grafted polymer side chains. These materials have attracted much attention for their ability to self-assemble into ordered structures with relatively large periodicities (over 50 nm), which are rarely achieved with simpler linear polymers. However, only self-assembly into lamellar and cylindrical phases has been reported in diblock bottlebrush materials.

A plasmon is the result of light interacting with the surface electrons in materials that meet specific dielectric requirements. Noble metals have long been used as plasmonic materials, yet other materials are capable of supporting surface plasmons. Recent work in the Van Duyne lab has shown that aluminum nanoparticles fabricated using a process known as nanosphere lithography (NSL) display plasmons throughout the UV-vis region.

Objective: To develop novel microfluidic flow cells that allow trapping of single DNA molecules and studies of the binding of sequence-specific probes to the trapped DNA.

The types of grain boundaries that make up the interfacial network within polycrystalline solids influence the properties and performance of the material. The population of grain boundary types is anisotropic, meaning that some of the types are found more frequently than others.

A team from IRG-1, working with collaborators at Argonne National Laboratory and the University of Utah, have demonstrated continuous room-temperature electrical tuning of the thermal conductivity of La0.5Sr0.5CoO3-d by a factor of more than five (a record for a single-step process) via ion-gel gating. Application of a gate voltage in these devices drives a transformation from a metallic perovskite phase to an insulating brownmillerite phase via the formation and migration of oxygen vacancies, realizing the record range of measured thermal conductivities.

The coupling of the magnetic and ferroelectric order in multiferroics produces new excitations of mixed magnetic (magnons) and lattice (phonons) character ; electro-magnons. The investigation of these novel excitations as has revealed that they are activated only through symmetric Heisenberg exchange, even in systems in which the static polarization arises from the relativistic antisymmetric exchange.