Biomedical subjects

D J Van Harlingen

Publications and source records attributed to D J Van Harlingen.

4 recordsLinked to original sources

PubMed2006

Dynamical superconducting order parameter domains in Sr2RuO4.

We present direct evidence for complex p-wave order parameter symmetry and the presence of dynamical chiral order parameter domains of the form px +/- ipy in the ruthenate superconductor Sr2RuO4. The domain structure creates differences in the magnetic field modulation of the critical current of Josephson junctions fabricated on orthogonal faces of Sr2RuO4 single crystals. Transitions between the chiral states of a domain or the motion of domain walls separating them generates telegraph noise in the critical current as a function of magnetic field or time and is responsible for hysteresis observed in field sweeps of the critical current. The presence of such domains confirms the p-wave triplet spin and complex (broken time-reversal symmetry) nature of the superconducting pairing state in Sr2RuO4.

Journal Article↗

PubMed2006

Doping controlled superconductor-insulator transition in Bi2Sr2-xLaxCaCu2O8+delta.

We show that the doping-controlled superconductor-insulator transition (SIT) in a high critical temperature cuprate system (Bi(2)Sr(2-x)La(x)CaCu(2)O(8+delta)) exhibits a fundamentally different behavior than is expected from conventional SIT. At the critical doping, the sheet resistance seems to diverge in the zero-temperature limit. Above the critical doping, the transport is universally scaled by a two-component conductance model. Below, it continuously evolves from weakly to strongly insulating behavior. The two-component conductance model suggests that a collective electronic phase-separation mechanism may be responsible for this unconventional SIT behavior.

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PubMed2004

Electronic transport in underdoped YBa2Cu3O7-delta nanowires: evidence for fluctuating domain structures.

We have measured the transport properties of a series of underdoped YBa(2)Cu(3)O(7-delta) nanowires fabricated with widths of 100-250 nm. We observe large telegraphlike fluctuations in the resistance between the pseudogap temperature T* and the superconducting transition temperature T(c), consistent with the formation and dynamics of a domain structure. We also find anomalous hysteretic steps in the current-voltage characteristics well below T(c).

Journal Article↗

PubMed2002

Experimental test for subdominant superconducting phases with complex order parameters in cuprate grain boundary junctions.

We propose and implement a direct experimental test for subdominant superconducting phases with broken time-reversal symmetry in d-wave superconductors. The critical current of 45 degrees -asymmetric grain boundary junctions is shown to be extremely sensitive to the predicted onset of a complex order parameter at (110) surfaces and near magnetic impurities. Measurements in pure Ni-doped YBa2Cu3O7-x junctions indicate that the symmetry at the surface is consistent with pure d-wave at all temperatures, putting limits on the magnitude and chiral domain structure of any subdominant symmetry component.

Journal Article↗