Abstract
Conductance of atom-sized contacts of In has been measured in ultrahigh vacuum at room temperature. The conductance histogram shows a peak at 0.83G0 (G0≡ 2e2/h is the conductance quantum) and a broad structure spanning from 1.5G0 to 4G0 with small peaks at ∼ 1.8G0, ∼ 2.5G0, and ∼ 3.3G0. The observed histogram is in overall agreement with the one obtained at 4 K (Makk et al., Phys. Rev. B 78, 045414 (2008)) but markedly differs from the histogram of Ga (Lewis et al., Solid State Commun. 109, 525 (1999)) which reveals no peak features at room temperature. Because the crystal structure of In is nearly FCC, our results support the conjecture suggested by Lewis et al. that the absence of peaks in the room-temperature histogram of Ga might be related to complexities in the crystal structure of Ga and its deformation characteristics. We also found that the same conductance trace sometimes appears repetitively in successive contact breaks. Such replication of the conductance trace is often observed at cryogenic temperatures but unexpected at room temperature particularly for soft metals such as In. [DOI: 10.1380/ejssnt.2011.85]
