arXiv subjects

Radovan Vranik

Publications and source records attributed to Radovan Vranik.

2 recordsLinked to original sources

arXiv2021

Stable $\pi$-radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) adsorbed at the elbows of $22\times\sqrt{3}$ reconstructed Au(111)

Stable organic radicals serve as model systems for investigating metal-free magnetic phenomena at (sub)nanometer length scales. We have investigated at the single-molecule level the stable $\pi$-radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) adsorbed at the elbow sites of the $22\times\sqrt{3}$ reconstructed Au(111) surface. Low-temperature scanning tunneling microscopy (STM) and -spectroscopy under ultrahigh vacuum conditions at 8~K reveal structural as well as frontier-orbital related electronic details of DPPH/Au(111). A Kondo-like spectroscopic signature indicates preservation of the unpaired electron spin state.

physics.ins-det↗

arXiv2020

Frequency-independent voltage amplitude across a tunnel junction

Radio-frequency (rf) scanning tunneling microscopy has recently been advanced to methods such as single-atom spin resonance. Such methods benefit from a frequency-independent rf voltage amplitude across the tunnel junction, which is challenging to achieve due to the strong frequency dependence of the rf attenuation in a transmission line. Two calibration methods for the rf amplitude have been reported to date. In this Note, we present an alternative method to achieve a frequency-independent rf voltage amplitude across the tunnel junction and show the results of this calibration. The presented procedure is applicable to devices that can deliver rf voltage to a tunnel junction.

physics.ins-det↗