Conductance steps in electromigrated Bi nanoconstrictions

• Published in: Physical chemistry chemical physics : PCCP 2013-04, Vol.15 (14), p.5132-5139
• Main Authors: Sangiao, Soraya, Michalik, Jan M, Casado, Laura, Martínez-Velarte, María C, Morellón, Luis, Ibarra, Manuel R, De Teresa, José M
• Format: Article
• Language: English
• Subjects: Bismuth; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductance; Electronic transport in condensed matter; Exact sciences and technology; Nanocomposites; Nanomaterials; Nanostructure; Physics; Ramps; Transport; Voltage
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp44133d

Bismuth nanostructures of initial lateral size of about 150 nm were successfully electromigrated at room temperature under high vacuum conditions through the application of voltage ramps and accurate control of their conductance. The imaging of the nanogap formation was followed by scanning electron microscopy. An appropriate design of the initial Bi nanostructures has made the electromigration process of semimetallic Bi feasible. Beyond the intrinsic interest in the generation of Bi structures with size tailored at the nanoscale, remarkable features have been observed in the time-dependent conductance curves of the Bi nanoconstrictions. In particular, sub-quantum conductance plateaus can be detected before the rupture of the constriction. An alternative procedure to study the transport through Bi nanoconstrictions has been explored using a focused-Ga-ion etching process with simultaneous control of the conductance. This second approach confirms the transport behavior observed in electromigrated Bi nanoconstrictions. Scanning electron microscopy image after a typical process of electromigration performed on a Bi nanoconstriction. The arrow indicates the breaking point of the constriction.