High-Frequency Signal Transmission Through Single-Atom Contacts Of Au And Pt

Signal transmission through atom-sized contacts of Au and Pt has been studied at room temperature for frequencies from 9 kHz to 1 GHz and for conductances (1-10)G(0) (G equivalent to 2e(2)/h is the quantum unit of conductance). We measured the frequency spectrum of S parameter S-21 = vertical bar S-21 vertical bar e(i theta) and found theta similar to 0 up to 1 GHz for all contacts irrespective of their conductance. Our observations directly prove that the atom-sized contacts of Au and Pt, including their single-atom contacts, behave as a pure resistance in the RF regime. (C) 2015 AIP Publishing LLC.