Two-step fabrication technique of gold tips for use in point-contact spectroscopy

Narasiwodeyar, S.M.; Dwyer, Matthew; Liu, M.; Park, W. K.; Greene, L. H.

doi:10.1063/1.4913661

Cited by 7 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Immediately after the ion beam etching, the sample holder was quickly attached to the PCS rig, typically within a few minutes and subsequently inserted into a cryostat (Quantum Design, PPMS DynaCool). In this study, we focus only upon the non-superconducting state, so all of the presented data were taken between 4 K and 25 K. Ballistic metallic junctions were formed in situ at low temperature using an electrochemically polished gold tip [26] mounted on a homemade PCS rig with piezo-driven nano-positioners [27]. The differential conductance of a junction, G(V) = dI/dV, was measured with a standard four-probe lock-in technique as a function of temperature and applied magnetic field.…”

Section: Experimental Methodsmentioning

confidence: 99%

Hybridization gap in the heavy-fermion compound UPd2Al3 via quasiparticle scattering spectroscopy

et al. 2017

Self Cite

View full text Add to dashboard Cite

We present results from point-contact spectroscopy of the antiferromagnetic heavy-fermion superconductor UPd 2 Al 3 : conductance spectra are taken from single crystals with two major surface orientations as a function of temperature and magnetic field, and analyzed using a theory of co-tunneling into an Anderson lattice. Spectroscopic signatures are clearly identified including the distinct asymmetric double-peak structure arising from the opening of a hybridization gap when a coherent heavy Fermi liquid is formed. Both the hybridization gap, found to be 7.2 ± 0.3 meV at 4 K, and the conductance enhancement above a flat background decrease upon increasing temperature. While the hybridization gap is extrapolated to remain finite up to ~28 K, close to the temperature around which the magnetic susceptibility displays a broad peak, the conductance enhancement vanishes at ~18 K, slightly above the antiferromagnetic transition temperature (T N  14 K). This rapid decrease of the conductance enhancement is understood as a consequence of the junction drifting away from the ballistic regime due to increased scattering off magnons associated with the localized U 5f electrons. This shows that while the hybridization gap opening is not directly associated with the antiferromagnetic ordering, its visibility in the conductance is greatly affected by the temperature-dependent magnetic excitations. Our findings are not only consistent with the 5f dual-nature picture in the literature but also shed new light on the interplay between the itinerant and localized electrons in UPd 2 Al 3 .

show abstract

Section: Experimental Methodsmentioning

confidence: 99%

Hybridization gap in the heavy-fermion compound UPd2Al3 via quasiparticle scattering spectroscopy

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since K2400 in Figure 1b was used to monitor the current, we could shut off the power supply immediately after the drop of current. 20 After the reaction was terminated, small salt crystals were sometimes found attached to the needle. In most cases they could be washed away with flowing water without breaking the fine shape of needle.…”

Section: Fig 2 Schematic Diagrams Of Two Conditions Of the Reaction P...mentioning

confidence: 99%

“…However, these metals are easy to dissolve under current. The method for etching Au with hydrochloric acid (HCl) has been proposed previously; 20 here we give the modified parameters in Table I. In comparison with Au, Cu has similar fabrication parameters since they share a similar electrochemical reaction mechanism.…”

Section: Fig 2 Schematic Diagrams Of Two Conditions Of the Reaction P...mentioning

confidence: 99%

“…[16][17][18] Tungsten, iron and cobalt tips also serve various purposes in atomic force microscopy (AFM) systems. 19 Electrochemical etching methods for several individual kinds of tips have been reported in previous literature, including gold 20 and tungsten, 21 which have been widely used in SPM and tunneling microscopy, including STM/S and PCS. Compared with electrochemical etching, mechanical methods of tip fabrication, including polishing and shearing, have some disadvantages.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Systematic electrochemical etching of various metal tips for tunneling spectroscopy and scanning probe microscopy

Zhang

Wang

Zhang

et al. 2021

Review of Scientific Instruments

View full text Add to dashboard Cite

Hard point-contact spectroscopy and scanning probe microscopy/spectroscopy are powerful techniques for investigating materials with strong expandability. To support these studies, tips with various physical and chemical properties are required. To ensure the reproducibility of experimental results, the fabrication of tips should be standardized, and a controllable and convenient system should be set up. Here a systematic methodology to fabricate various tips is proposed, involving electrochemical etching reactions. The reaction parameters fall into four categories: solution, power supply, immersion depth, and interruption. An etching system was designed and built so that these parameters could be accurately controlled. With this system, etching parameters for copper, silver, gold, platinum/iridium alloy, tungsten, lead, niobium, iron, nickel, cobalt, and permalloy were explored and standardized. Among these tips, silver and niobium's new recipes were explored and standardized. Optical and scanning electron microscopies were performed to characterize the sharp needles. Relevant point-contact experiments were carried out with an etched silver tip to confirm the suitability of the fabricated tips. I.

show abstract

“…33). QPS junctions were formed using Au tips [34] in a custom-built rig [35] and differential conductance across the junction was measured using a standard fourprobe lock-in technique. The conductance data were analyzed using the Maltseva-Dzero-Coleman (MDC) model ( [36], also see Sect.…”

mentioning

confidence: 99%

Origin of gap-like behaviors in URu$_2$Si$_2$: Combined study via quasiparticle scattering spectroscopy and resistivity measurements

Zhang,

Chappell,

Pouse

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

We address two long-standing questions regarding the hidden order in URu2Si2: Is it associated with the hybridization process, and what are the distinct roles played by the localized and itinerant electrons? Our quasiparticle scattering spectroscopy reveals a hybridization gap ubiquitous in the entire phase space spanned by P and Fe substitutions in URu2Si2, including the no-order and antiferromagnetic regions, with minimal change upon crossing the phase boundary. This indicates its opening isn't associated with the ordering, and thus localized electrons must be the major player. Towards a consistent understanding of all the other gap-like behaviors observed only below transition temperatures, we analyze the electrical resistivity using a model in which gapped bosonic excitations are the dominant scattering source. With their stiffness set to follow an unusual temperature dependence (decreasing with decreasing temperature), this model fits all of our resistivity data well including the jump at the transition. Remarkably, the extracted gap increases slowly with increasing Fe content, similarly to the gap detected by inelastic neutron scattering at Q1 = (1.4, 0, 0), suggesting a common origin. Such a model can also naturally explain the Hall effect temperature dependence without invoking Fermi surface gapping.

show abstract

Two-step fabrication technique of gold tips for use in point-contact spectroscopy

Cited by 7 publications

References 27 publications

Hybridization gap in the heavy-fermion compound UPd2Al3 via quasiparticle scattering spectroscopy

Hybridization gap in the heavy-fermion compound UPd2Al3 via quasiparticle scattering spectroscopy

Systematic electrochemical etching of various metal tips for tunneling spectroscopy and scanning probe microscopy

Origin of gap-like behaviors in URu$_2$Si$_2$: Combined study via quasiparticle scattering spectroscopy and resistivity measurements

Contact Info

Product

Resources

About