Electron Transport and Quantum Control

Welcome to the website of Professor Wulfhekel's Research Unit "Electron Transport and Quantum Control". We are involved in the Research Areas Quantum Transport and Correlations and Molecular Electronics at the Institute of Nanotechnology (INT) at the Karlsruhe Institute of Technology.


Molecular Graph Paper
Molecular Graph Paper

Using the tip of an STM, the acetyl group that sticks out of a molecular film can be removed in a controlled way. The chemically modified molecule can readily be distinguished from the original ones so that writing and reading information on the nanoscale becomes possible.

Angew. Chem. Int. Ed. 56 (28), 8290, (2017)

Sketch of Spiro A in the STM junction
An electrically actuated molecular toggle switch

 We realized single molecule switches based on electrostatic forces: We studied a spirobifluorene variant with a well-defined spatial arrangement of the nitrile head group. This allows to exert forces on the molecule by application of electric fields.

Nat. Commun. 6, 14672 (2017)

thermoelectric effects in superconductor-ferromagnet structures
Large thermoelectric effects in superconductor-ferromagnet structures

We observe a spin-dependent Seebeck coefficient of about -100 μV/K due to a coupling of spin and heat currents in nanoscale superconductor-ferromagnet structures.

Kolenda et al., Phys. Rev. Lett. 116, 097001 (2016)
EuS/aluminum structure
Spin transport in superconductors manipulated by spin-active scattering

We observe spin injection and long-range spin transport in nanoscale aluminum structures on top of the ferromagnetic insulator europium sulfide. Our results demonstrate that spin transport in superconductors can be manipulated by spin-active scattering.

Read more in Wolf et al., Phys. Rev. B 90, 144509 (2014)

MEC in Fe island
Dynamics of Electrically Driven Martensitic Phase Transitions in Fe Nanoislands

We studied the dynamics and energetics of the martensitic phase transition in the electric field on the nanometer scale.

Phys. Rev. Lett. 111, 167601 (2013)

Tripodal Molecule on Au(111)
Tripodal Molecule: Orientation-Dependent Coupling and Electronic Properties

We investigated the conductance behavior of a new three-dimensional molecule by scanning tunneling microscopy and density functional theory.

ACS Nano 7, 6170–6180 (2013)

Homebuilt Low-Temperature STM

Our new homebuilt 4 K STM is working fine. First measurements on organic molecules show extremely low noise levels and neglegible drift.

Nanoparticles digging the world´s smallest tunnels

Nickel nanoparticles are used to etch world's smallest tunnels into graphite

Helmholtz annual report 2013 (S.44) 


Nature Communications 4 (2013) 1379

Spin transport in superconductor hybrid structures
Long-range spin transport in nanoscale superconductors

In nanoscale superconductors with a Zeeman splitting, spin-polarized quasiparticles can be transported over suprisingly long distances. Read more in Hübler et al., Phys. Rev. Lett. 109, 207001 (2012)

Single molecule GMR

We measured the giant magnetoresistance of single Hydrogen-Phtalocyanine molecules of about 60%. This value is extremely large in view of the fact that they do not contain any magnetic atoms.

Nature Nanotechnology 6 (2011) 185-189