Ga elements, Ga films, Ga/X junctions

Kieselmann, G.

doi:10.1007/10332996_67

Cited by 2 publications

(2 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the [001] oriented single crystal (Czochralski method), in 0.1 T field, we observe a sharp downward turn around 6.4 K. We were able to correlate this feature to the onset of superconductivity from tiny amounts of Ga inclusions in thin film form (T c = 7.6 K). 58 The gallium inclusions were removed by grinding the sample and washing it with diluted hydrochloric acid (H 2 O:HCl = 1:1). The susceptibility measurements on the so obtained polycrystalline sample did not show any downturn at low temperatures.…”

Section: Heat Capacity and Susceptibility Measurementsmentioning

confidence: 99%

Phonon-drag effect inFeGa3

et al. 2014

View full text Add to dashboard Cite

The thermoelectric properties of single-and polycrystalline FeGa3 are systematically investigated over a wide temperature range. At low temperatures, below 20 K, previously not known pronounced peaks in the thermal conductivity (400-800 W K −1 m −1 ) with corresponding maxima in the thermopower (in the order of -16000 µV K −1 ) were found in single crystalline samples. Measurements in single crystals along [100] and [001] directions indicate only a slight anisotropy in both the electrical and thermal transport. From susceptibility and heat capacity measurements, a magnetic or structural phase transition was excluded. Using density functional theory-based calculations, we have revisited the electronic structure of FeGa3 and compared the magnetic (including correlations) and non-magnetic electronic densities of states. Thermopower at fixed carrier concentrations are calculated using semi-classical Boltzmann transport theory, and the calculated results match fairly with our experimental data. The inclusion of strong electron correlations treated in a mean-field manner (by LSDA+U ) does not improve this comparison, rendering strong correlations as the sole explanation for the low temperature enhancement unlikely. Eventually, after a careful review, we assign the peaks in the thermopower as a manifestation of the phonon-drag effect, which is supported by thermopower measurements in a magnetic field.

show abstract

Section: Heat Capacity and Susceptibility Measurementsmentioning

confidence: 99%

Phonon-drag effect inFeGa3

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Since Ga has an equilibrium solubility in Ge of about 1 at.% and Ge is practically insoluble in Ga [19], the formation of pure metallic Ga precipitates or even films might occur. Crystalline and amorphous Ga allotropes are superconductors with critical temperatures up to 8.5 K [20]. Even nanosized Ga inclusions in porous glasses [21] or ultrathin amorphous Ga films [22] exhibit superconductivity around 7 K. Indeed, comparable critical temperatures (6-7 K) can be achieved by rapid thermal annealing (RTA) for 60 s of SiO 2 -capped Si [7] or Ge films [8] with a 13 at.% Ga peak concentration in the as-implanted state.…”

Section: Introductionmentioning

confidence: 99%

Depth-resolved transport measurements and atom-probe tomography of heterogeneous, superconducting Ge:Ga films

Heera¹,

Fiedler²,

Naumann³

et al. 2014

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Ge films with a mean Ga content of about 8 and 1 at.% hole concentration can be fabricated by ion implantation and subsequent flash-lamp annealing. The Ge:Ga films become superconducting below critical temperatures in the range between 1 and 2 K depending on the film resistance. The change in the macroscopic transport properties during step-wise surface etching can be described by a homogeneously doped layer model. However, the Ga distribution is extremely heterogeneous on the nanoscale. Atom-probe tomography analyses reveal the presence of Ga-rich precipitates with Ga clusters of up to 10 000 atoms. Since no percolating Ga clusters exist, it can be supposed that the heavy doping of Ge enables a coherent superconducting state via the proximity effect.

show abstract

Ga elements, Ga films, Ga/X junctions

Cited by 2 publications

References 51 publications

Phonon-drag effect inFeGa3

Phonon-drag effect inFeGa3

Depth-resolved transport measurements and atom-probe tomography of heterogeneous, superconducting Ge:Ga films

Contact Info

Product

Resources

About