Limits...
High temperature superconducting FeSe films on SrTiO3 substrates.

Sun Y, Zhang W, Xing Y, Li F, Zhao Y, Xia Z, Wang L, Ma X, Xue QK, Wang J - Sci Rep (2014)

Bottom Line: For the 1-UC FeSe on conductive STO substrate (Nb-STO), the magnetization versus temperature (M-T) measurement shows a drop crossover around 85 K.For the FeSe films on insulating STO substrate, systematic transport measurements were carried out and the sheet resistance of FeSe films exhibits Arrhenius TAFF behavior with a crossover from a single-vortex pinning region to a collective creep region.More intriguing, sign reversal of Hall resistance with temperature is observed, demonstrating a crossover from hole conduction to electron conduction above TC in 1-UC FeSe films.

View Article: PubMed Central - PubMed

Affiliation: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2].

ABSTRACT
Interface enhanced superconductivity at two dimensional limit has become one of most intriguing research directions in condensed matter physics. Here, we report the superconducting properties of ultra-thin FeSe films with the thickness of one unit cell (1-UC) grown on conductive and insulating SrTiO3 (STO) substrates. For the 1-UC FeSe on conductive STO substrate (Nb-STO), the magnetization versus temperature (M-T) measurement shows a drop crossover around 85 K. For the FeSe films on insulating STO substrate, systematic transport measurements were carried out and the sheet resistance of FeSe films exhibits Arrhenius TAFF behavior with a crossover from a single-vortex pinning region to a collective creep region. More intriguing, sign reversal of Hall resistance with temperature is observed, demonstrating a crossover from hole conduction to electron conduction above TC in 1-UC FeSe films.

No MeSH data available.


Hall results of sample No.2 (1-UC FeSe films grown on HR STO) and sample No.4 (2-UC FeSe films grown on HR STO) after subtracting the influence of the protection layer.(a) & (c), Rxy vs magnetic field curves at different temperatures of sample No.2 and No.4 subtracting the background of protection layers, respectively. (b) & (d), Hall sensitivity and the carrier density of sample No.2 and No.4 at different temperatures obtained from the data in (a) and (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4129414&req=5

f5: Hall results of sample No.2 (1-UC FeSe films grown on HR STO) and sample No.4 (2-UC FeSe films grown on HR STO) after subtracting the influence of the protection layer.(a) & (c), Rxy vs magnetic field curves at different temperatures of sample No.2 and No.4 subtracting the background of protection layers, respectively. (b) & (d), Hall sensitivity and the carrier density of sample No.2 and No.4 at different temperatures obtained from the data in (a) and (c).

Mentions: The Hall resistance (Rxy) of FeSe films is measured by sweeping the magnetic field at a fixed temperature. The temperature stabilization is better than 0.1%. The distance between the Hall voltage electrodes is about 1.5 mm for all measured samples. Figures 4(a)–4(b) show the data of Rxy vs magnetic field (Rxy(H)) at different temperatures from 40 K to 150 K of samples No.2 and No.4, which exhibit good linear relation. In order to subtract the influence of FeTe protection layer, transport properties of reference sample (10 UC FeTe grown on insulating STO substrate) were studied. The sheet resistance of the reference sample varies with temperature (Rsq(T)) under different magnetic fields (0 T, 9 T and −9 T) are exhibited in Fig. 4(c). Figure 4(d) shows the Rxy(H) curves of the reference sample at different temperatures. The Hall conductance of pure FeSe films (removed the influence of FeTe layers) can be calculated by . After removing the influence of FeTe protection layer, the Hall resistance (Rsq(xy)-FeSe) of the pure FeSe film sample is re-obtained by conversing from Hall conductance of FeSe films, (where ), which are plotted in Figs. 5(a) and 5(c) for sample No.2 and No.4, respectively.


High temperature superconducting FeSe films on SrTiO3 substrates.

Sun Y, Zhang W, Xing Y, Li F, Zhao Y, Xia Z, Wang L, Ma X, Xue QK, Wang J - Sci Rep (2014)

Hall results of sample No.2 (1-UC FeSe films grown on HR STO) and sample No.4 (2-UC FeSe films grown on HR STO) after subtracting the influence of the protection layer.(a) & (c), Rxy vs magnetic field curves at different temperatures of sample No.2 and No.4 subtracting the background of protection layers, respectively. (b) & (d), Hall sensitivity and the carrier density of sample No.2 and No.4 at different temperatures obtained from the data in (a) and (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129414&req=5

f5: Hall results of sample No.2 (1-UC FeSe films grown on HR STO) and sample No.4 (2-UC FeSe films grown on HR STO) after subtracting the influence of the protection layer.(a) & (c), Rxy vs magnetic field curves at different temperatures of sample No.2 and No.4 subtracting the background of protection layers, respectively. (b) & (d), Hall sensitivity and the carrier density of sample No.2 and No.4 at different temperatures obtained from the data in (a) and (c).
Mentions: The Hall resistance (Rxy) of FeSe films is measured by sweeping the magnetic field at a fixed temperature. The temperature stabilization is better than 0.1%. The distance between the Hall voltage electrodes is about 1.5 mm for all measured samples. Figures 4(a)–4(b) show the data of Rxy vs magnetic field (Rxy(H)) at different temperatures from 40 K to 150 K of samples No.2 and No.4, which exhibit good linear relation. In order to subtract the influence of FeTe protection layer, transport properties of reference sample (10 UC FeTe grown on insulating STO substrate) were studied. The sheet resistance of the reference sample varies with temperature (Rsq(T)) under different magnetic fields (0 T, 9 T and −9 T) are exhibited in Fig. 4(c). Figure 4(d) shows the Rxy(H) curves of the reference sample at different temperatures. The Hall conductance of pure FeSe films (removed the influence of FeTe layers) can be calculated by . After removing the influence of FeTe protection layer, the Hall resistance (Rsq(xy)-FeSe) of the pure FeSe film sample is re-obtained by conversing from Hall conductance of FeSe films, (where ), which are plotted in Figs. 5(a) and 5(c) for sample No.2 and No.4, respectively.

Bottom Line: For the 1-UC FeSe on conductive STO substrate (Nb-STO), the magnetization versus temperature (M-T) measurement shows a drop crossover around 85 K.For the FeSe films on insulating STO substrate, systematic transport measurements were carried out and the sheet resistance of FeSe films exhibits Arrhenius TAFF behavior with a crossover from a single-vortex pinning region to a collective creep region.More intriguing, sign reversal of Hall resistance with temperature is observed, demonstrating a crossover from hole conduction to electron conduction above TC in 1-UC FeSe films.

View Article: PubMed Central - PubMed

Affiliation: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2].

ABSTRACT
Interface enhanced superconductivity at two dimensional limit has become one of most intriguing research directions in condensed matter physics. Here, we report the superconducting properties of ultra-thin FeSe films with the thickness of one unit cell (1-UC) grown on conductive and insulating SrTiO3 (STO) substrates. For the 1-UC FeSe on conductive STO substrate (Nb-STO), the magnetization versus temperature (M-T) measurement shows a drop crossover around 85 K. For the FeSe films on insulating STO substrate, systematic transport measurements were carried out and the sheet resistance of FeSe films exhibits Arrhenius TAFF behavior with a crossover from a single-vortex pinning region to a collective creep region. More intriguing, sign reversal of Hall resistance with temperature is observed, demonstrating a crossover from hole conduction to electron conduction above TC in 1-UC FeSe films.

No MeSH data available.