Johannes Barth

Surface and Interface Physics

Technical University of Munich

Department of Physics

James-Franck-Str. 1

85747 Garching

+49 89 289 12609


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Research focus: quantum materials, molecular spin systems, quantum nanosystems

Research is focused on the exploration of interfacial and molecular nanosystems and quantum materials, notably including the design and engineering of functional metal-organic architectures.

Atomistic investigation of quantum materials and phenomena

We aim at a detailed characterization of the electronic and geometric structure of solid state, molecular and hybrid quantum materials, notably affording direct insights by advanced scanning probe microscopy and spectroscopy tools. Key issues are the control of surfaces & thin films of quantum materials emanating from the effects of deposition of atoms and molecules self-assembling in distinct architectures, and seeeing with utmost spatial resolution precisely what is happening to electronic and structural properties at the atomic scale.

Selected publications

  • Tunable quantum dot arrays formed from self-assembled metal-organic networks. Physical Review Letters 106, 026802 (2011)
  • Supramolecular gratings for tuneable confinement of electrons on metal surfaces. Nature Nanotechnology 2, 99 (2007).

Tailoring molecular spin systems

Our research explores potential molecular qubits based on coordination compounds anchored at interfaces or embedded in tailored nanoscale environments, such as metallosupramolecular networks with rare-earth centers or tailored metal-organic systems, including, e.g., d-f hybrid architectures or heterometallic ring systems. An important issue for tackling molecule-based quantum information technologies is notably the (supra)molecular organization in well-defined arrays and complex architectures, as well as the bottom-up fabrication of tailored single-atom quantum magnets.

Selected publications

  • Quasicrystallinity expressed in two-dimensional coordination networks. Nature Chem. 8, 657 (2016).
  • Supramolecular control of the magnetic anisotropy in two-dimensional high-spin Fe arrays at a metal interface. Nature Mater. 8, 189 (2009).


Atomistic investigation of surface characteristics and electronic features at high-purity FeSi(110) presenting interfacial metallicity

B. Yang, M. Uphoff, Y.-Q. Zhang, J. Reichert, A.P. Seitsonen, A. Bauer, C. Pfleiderer, J.V. Barth

PNAS 118 , e2021203118 (2021).

Show Abstract

Iron silicide (FeSi) provides multiple fascinating features whereby intriguing functional properties bearing significant application prospects were recognized. FeSi is understood notably as a correlated d-electron narrow-gap semiconductor and a putative Kondo insulator, hosting unconventional quasiparticles. Recently, metallic surface conduction channels were identified at cryogenic conditions and suggested to play a key role in the resistivity of high-quality single-crystalline specimens. Motivated by these findings, we prepared and closely examined a FeSi(110) surface with atomistically defined termination and topography. In the low-temperature regime, where surface metallicity emerges, the electronic band gap undergoes a subtle evolution. The pertaining key features, asymmetrization of the gap shape and formation of in-gap states, underscore the similarity of FeSi to unequivocal topological Kondo insulator materials.

DOI: 10.1073/pnas.2021203118

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