NANOWIRES ON STEPPED METAL-SURFACES

The electronic properties of solids can be tailored by structuring the m on the nanometer scale. Such a program is becoming reality as surfac e analysis techniques and sophisticated growth methods are merging. He re, we present results of a venture into one-dimensional nanostructure s, grown by decoration of steps at metal surfaces. The growth modes an d electronic states are studied using scanning tunneling microscopy (S TM) and inverse photoemission. Two-dimensional analogs of Stranski-Kra stanov and layer-by-layer growth are found for Cu on stepped Mo(110) a nd W(110), respectively. Contrast between different metals is achieved in STM pictures by resonant tunneling via surface states and image st ates, with the latter providing a map of the work function. The Limit of single atomic rows decorating step edges is studied by inverse phot oemission, and an energy shift of 0.4 eV is found for electronic state s of step atoms. Stripe structures are attractive for the study of two - versus one-dimensional magnetism, for magnetoresistive sensors, and in the design of anisotropic materials.