Compact design of a low temperature XY stage scanning tunneling microscope

Dubois, Cédric; Bisson, Peter; Manuel, Α. A.; Fischer, Ø.; Reymond, S.

doi:10.1063/1.2194489

Cited by 21 publications

(11 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Scanning Tunneling Spectroscopy (STS) is an ideal tool for this, particularly since it allows one to map the vortices in real space and also access the normal state below T c by probing their cores [17,18,19,20]. In this Letter we present a detailed STS study of KOs 2 O 6 single crystals, including the first vortex imaging in this material.The KOs Our measurements are carried out using a home-built low temperature scanning tunneling microscope featuring a compact nanopositioning stage [21] to target the smallsized crystals. Electrochemically etched iridium tips are used for STS measurements on as-grown single crystal surfaces and the differential conductivity was measured using a standard AC lock-in technique.…”

mentioning

confidence: 99%

“…The KOs Our measurements are carried out using a home-built low temperature scanning tunneling microscope featuring a compact nanopositioning stage [21] to target the smallsized crystals. Electrochemically etched iridium tips are used for STS measurements on as-grown single crystal surfaces and the differential conductivity was measured using a standard AC lock-in technique.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of theβ-PyrochloreKOs2O6

et al. 2008

Self Cite

View full text Add to dashboard Cite

We performed the first scanning tunneling spectroscopy measurements on the pyrochlore superconductor KOs2O6 (Tc = 9.6 K) in both zero magnetic field and the vortex state at several temperatures above 1.95 K. This material presents atomically flat surfaces, yielding spatially homogeneous spectra which reveal fully-gapped superconductivity with a gap anisotropy of 30%. Measurements performed at fields of 2 and 6 T display a hexagonal Abrikosov flux line lattice. From the shape of the vortex cores, we extract a coherence length of 31-40Å, in agreement with the value derived from the upper critical field Hc2. We observe a reduction in size of the vortex cores (and hence the coherence length) with increasing field which is consistent with the unexpectedly high and unsaturated upper critical field reported.PACS numbers: 74.70. Dd, 74.50.+r, 74.25.Qt The discovery of superconductivity in the β-pyrochlore osmate compounds AOs 2 O 6 (A = K, Rb, Cs) [1] has highlighted the question of the origin of superconductivity in classes of materials which possess geometrical frustration [2,3]. Interest has been predominantly focused on the highest-T c compound KOs 2 O 6 which presents many striking characteristics. In particular, the absence of inversion symmetry in its crystal structure [4] raises the question of its Cooper pair symmetry and the possibility of spin singlet-triplet mixing [5,6].The pyrochlore osmate compound KOs 2 O 6 displays a critical temperature T c = 9.6 K, the largest in its class of materials (CsOs 2 O 6 and RbOs 2 O 6 which differ only by the nature of the alkali ion have T c s of 3.3 and 6.3 K respectively). Although band structure calculations show that the K ion does not influence the density of states (DOS) at the Fermi level [7,8], it seems to affect several key properties [9]. In particular, the first order phase transition revealed by specific heat measurements in magnetic fields at the temperature T p ≈ 7.5 K has been ascribed to a "freezing" of its rattling motion [10]. The negative curvature of the resistivity as a function of temperature also indicates a large electron-phonon scattering [11]. Specific heat measurements [12] suggest the coexistence of strong electron correlations and strong electron-phonon coupling, two generally antagonistic phenomena with respect to the superconducting pairing symmetry. The nature of the symmetry remains a controversial subject in the literature. NMR [13] and µSR [14] data suggest anisotropic gap functions with nodes whereas thermal conductivity experiments [15] favor a fully-gapped state.The peculiar behavior of KOs 2 O 6 is demonstrated by its upper critical magnetic field H c2 , whose temperature dependence is linear down to sub-Kelvin temperatures and whose amplitude is above the Clogston limit [16]. One possible interpretation is the occurrence of spin-triplet superconductivity driven by spinorbit coupling [5,6]. Alternatively, it has also been suggested that this behavior can be explained by the peculiar topology of the Fermi surface (FS) sheets of KOs ...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of theβ-PyrochloreKOs2O6

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…We obtained flat ͑001͒ surfaces by cleaving the crystals using a blade under an optical microscope. The STS measurements were carried out using a home-built scanning tunneling microscope, featuring an XY stage 16 to target the micrometer-sized crystals. We use electrochemically etched Ir tips and measure the differential conductivity using a standard lock-in technique.…”

mentioning

confidence: 99%

Node-like excitations in superconductingPbMo6S8probed by scanning tunneling spectroscopy

et al. 2007

Self Cite

View full text Add to dashboard Cite

We present a scanning tunneling spectroscopy study on the Chevrel phase PbMo 6 S 8 , an extreme type-II superconductor with a coherence length only slightly larger than in high-T c cuprates. Tunneling spectra measured on atomically flat terraces are spatially homogeneous and show well-defined coherence peaks. The low-energy spectral weight, the zero bias conductance, and the temperature dependence of the gap are incompatible with a conventional isotropic s-wave interpretation, revealing the presence of low-energy excitations in the superconducting state. We show that our data are consistent with the presence of nodes in the superconducting gap.

show abstract

“…It is substantially simpler than a more recent design. 26 While it is possible to build a three-dimensional positioner and scanner in a single device, 27 this has only been tested with an optical microscope that is not as sensitive to vibrations as is a scanning tunneling microscope ͑STM͒ or an atomic force microscope ͑AFM͒. For microscopes that are not affected by the presence of magnetic materials, e.g., a simple AFM, the spring in our setup may be replaced by a magnet and a -metal plate.…”

Section: X-y Positionermentioning

confidence: 99%

Scanning Hall probe microscopy of a diluted magnetic semiconductor

Kweon

Samarth

Lozanne

2009

Journal of Applied Physics

View full text Add to dashboard Cite

We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga0.94Mn0.06As films grown by molecular beam epitaxy. We find that the magnetic domains are 2–4 μm wide and fairly stable with temperature. Magnetic clusters are observed above TC, which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

show abstract

Compact design of a low temperature XY stage scanning tunneling microscope

Cited by 21 publications

References 27 publications

Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of theβ-PyrochloreKOs2O6

Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of theβ-PyrochloreKOs2O6

Node-like excitations in superconductingPbMo6S8probed by scanning tunneling spectroscopy

Scanning Hall probe microscopy of a diluted magnetic semiconductor

Contact Info

Product

Resources

About