Quartz Crystal Microbalance Studies of Atomic Scale Friction

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****Technical Abstract****The late 20th century marked a renaissance in fundamental areas of tribology, sparked by new experimental and theoretical techniques capable of studying the friction in atomic-scale geometries. This project involves the use of one such technique, namely the Quartz Crystal Microbalance (QCM), to probe critical topics in this field, taking advantage of extraordinary recent progress in graphene and C60 materials as samples formed on the QCM. A first study will establish the validity of theories that predict important new physics phenomena for lattice gas systems pinned in place on C60 substrates. Novel crystalline states in the pinned adsorbed systems may reveal interesting information about the ordering of a 2D solid, and even, perhaps, a novel supersolid phase of matter for helium. A second study will document the delicate balance between frictional heating effects in sliding adsorbed films, and the cooling that occurs when frictional heat causes the films to evaporate. The third study will document the conditions under which external magnetic fields can be used to control atomic scale friction, and represents a major transition in this field from passive characterization to active external control. A complimentary educational component includes (1) ongoing participation of graduate and undergraduate students in the research, and (2) direct dissemination of state-of-the-art information on friction to general audiences through lectures and written reviews.****Non-Technical Abstract****As the price of energy rises, and the need to conserve both energy and raw materials becomes increasingly urgent, physicists' rush to understand basic energy loss processes is accelerating. The late 20th century marked a renaissance in fundamental areas of tribology (the study of friction and wear), sparked by a number of new experimental and theoretical techniques capable of studying the force of friction at scales as small as an atom. This project involves three studies using one such technique, the Quartz Crystal Microbalance (QCM), to probe critical topics in this field, taking advantage of extraordinary recent progress in graphene and C60 materials that are now widely available. The first is a study of the validity of theories that predict important new physics phenomena for pinned atom and possibly a novel zero-friction "supersolid" phase of matter. The second is a study of the delicate balance between frictional heating effects and the cooling that occurs when frictional heat causes the films to evaporate. The third study documents the conditions under which external magnetic fields can be used to control atomic scale friction, in analogy with macroscopic magnetic levitation effects. Graduate and undergraduate students will participate in all aspects of the research. The students will graduate with an arsenal of experimental and theoretical knowledge that will prepare them to attack challenging societal problems in a host of technical areas far beyond the present topic.