Electrical current through individual pairs of phosphorus donor atoms and silicon dangling bonds.

Nuclear spins of phosphorus [P] donor atoms in crystalline silicon are among the most coherent qubits found in nature. For their utilization in scalable quantum computers, distinct donor electron wavefunctions must be controlled and probed through electrical coupling by application of either highly localized electric fields or spin-selective currents. Due to the strong modulation of the P-donor wavefunction by the silicon lattice, such electrical coupling requires atomic spatial accuracy. Here, the spatially controlled application of electrical current through individual pairs of phosphorus donor electron states in crystalline silicon and silicon dangling bond states at the crystalline silicon (100) surface is demonstrated using a high-resolution scanning probe microscope operated under ultra-high vacuum and at a temperature of 4.3 K. The observed pairs of electron states display qualitatively reproducible current-voltage characteristics with a monotonous increase and intermediate current plateaus.

Mapping the force field of a hydrogen-bonded assembly.

Hydrogen bonding underpins the properties of a vast array of systems spanning a wide variety of scientific fields. From the elegance of base pair interactions in DNA to the symmetry of extended supramolecular assemblies, hydrogen bonds play an essential role in directing intermolecular forces. Yet fundamental aspects of the hydrogen bond continue to be vigorously debated. Here we use dynamic force microscopy (DFM) to quantitatively map the tip-sample force field for naphthalene tetracarboxylic diimide molecules hydrogen-bonded in two-dimensional assemblies. A comparison of experimental images and force spectra with their simulated counterparts shows that intermolecular contrast arises from repulsive tip-sample interactions whose interpretation can be aided via an examination of charge density depletion across the molecular system. Interpreting DFM images of hydrogen-bonded systems therefore necessitates detailed consideration of the coupled tip-molecule system: analyses based on intermolecular charge density in the absence of the tip fail to capture the essential physical chemistry underpinning the imaging mechanism.

Collaboration in task analysis for developing a database to record the essential clinical behaviors of nursing students.

This database for recording the Essential Clinical Behaviors of nursing students is the result of collaboration between nursing faculty and an instructional designer at Ball State University in Muncie, Indiana. The database was developed to aid nursing instructors in recording and tracking those student behaviors and skills essential to nursing education. The developers of the database are continuing to work toward the goal of having students record data and prepare reports. This would enable the students to be more self-directed in seeking appropriate and essential clinical experiences.