@article{Heinrich2025b,

title = {Exploring the evolution and future of ESR-STM},

author = {Andreas J. Heinrich and Noah Al-Shamery},

editor = {Deutsche Bunsen-Gesellschaft für physikalische Chemie e.V., Frankfurt},

url = {https://bunsen.de/bmo/exploring-the-evolution-and-future-of-esr-stm},

year  = {2025},

date = {2025-03-31},

urldate = {2025-03-31},

journal = {Bunsen-Magazin},

volume = {3},

pages = {101-102},

abstract = {Andreas Heinrich is a pioneer in the field of scanning probe microscopy and a leading figure in the development of Electron Spin Resonance Scanning Tunneling Microscopy (ESR-STM). His work has enabled researchers to probe and manipulate individual spins with unprecedented precision. In this interview, he hares insights into the origins, challenges, and future directions of ESR-STM, offering a glimpse into the next frontiers of atomic-scale magnetic measurements.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Singha2017,

title = {4f occupancy and magnetism of rare-earth atoms adsorbed on metal substrates},

author = {Aparajita Singha and Romana Baltic and Fabio Donati and Christian Wäckerlin and Jan Dreiser and Luca Persichetti and Sebastian Stepanow and Pietro Gambardella and Stefano Rusponi and Harald Brune},

url = {https://link.aps.org/doi/10.1103/PhysRevB.96.224418},

doi = {10.1103/PhysRevB.96.224418},

issn = {24699969},

year  = {2017},

date = {2017-12-01},

urldate = {2017-12-01},

journal = {Physical Review B},

volume = {96},

number = {22},

pages = {224418},

publisher = {IOP Publishing},

abstract = {We report x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements as well as multiplet calculations for Dy, Ho, Er, and Tm atoms adsorbed on Pt(111), Cu(111), Ag(100), and Ag(111). In the gas phase, all four elements are divalent and we label their 4f occupancy as 4fn. Upon surface adsorption, and depending on the substrate, the atoms either remain in that state or become trivalent with 4fn-1 configuration. The trivalent state is realized when the sum of the atomic correction energies (4f→5d promotion energy Efd+ intershell coupling energy δEc) is low and the surface binding energy is large. The latter correlates with a high substrate density of states at the Fermi level. The magnetocrystalline anisotropy of trivalent RE atoms is larger than the one of divalent RE atoms. We ascribe this to the significantly smaller covalent radius of the trivalent state compared to the divalent one for a given RE element. For a given valency of the RE atom, the anisotropy is determined by the overlap between the spd states of the RE and the d states of the surface. For all investigated systems, the magnetization curves recorded at 2.5 K show absence of hysteresis indicating that magnetic relaxation is faster than about 10 s.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Baumann2015,

title = {Electron paramagnetic resonance of individual atoms on a surface},

author = {Susanne Baumann and William Paul and Taeyoung Choi and Christopher P. Lutz and Arzhang Ardavan and Andreas J. Heinrich},

doi = {10.1126/science.aac8703},

issn = {1095-9203},

year  = {2015},

date = {2015-10-23},

journal = {Science},

volume = {350},

number = {6259},

pages = {417--420},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {EPR, one atom at a time

          

            Electron paramagnetic resonance (EPR) usually detects atoms with unpaired electrons as ensemble averages. Baumann

            et al.

            used a spin-polarized scanning tunneling microscope tip to measure EPR spectra of single iron atoms adsorbed on a magnesium oxide surface at cryogenic temperatures. The measurement depends on the atomic orbital symmetry; no signal was observed for cobalt atoms under the same conditions

          

          

            Science

            , this issue p.

            417

          },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rau2014,

title = {Reaching the magnetic anisotropy limit of a 3d metal atom},

author = {Ileana G. Rau and Susanne Baumann and Stefano Rusponi and Fabio Donati and Sebastian Stepanow and Luca Gragnaniello and Jan Dreiser and Cinthia Piamonteze and Frithjof Nolting and Shruba Gangopadhyay and Oliver R. Albertini and Roger M. Macfarlane and Christopher P. Lutz and Barbara A. Jones and Pietro Gambardella and Andreas J. Heinrich and Harald Brune},

doi = {10.1126/science.1252841},

issn = {1095-9203},

year  = {2014},

date = {2014-05-30},

urldate = {2014-05-30},

journal = {Science},

volume = {344},

number = {6187},

pages = {988--992},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {<jats:title>Maximizing atomic magnetic memory</jats:title>

          <jats:p>

            A study of the magnetic response of cobalt atoms adsorbed on oxide surfaces may lead to much denser storage of data. In hard drives, data are stored as magnetic bits; the magnetic field pointing up or down corresponds to storing a zero or a one. The smallest bit possible would be a single atom, but the magnetism of a single atom —its spin—has to be stabilized by interactions with heavy elements or surfaces through an effect called spin-orbit coupling. Rau

            <jats:italic>et al.</jats:italic>

            (see the Perspective by Khajetoorians and Wiebe) built a model system in pursuit of single-atom bits—cobalt atoms adsorbed on magnesium oxide. At temperatures approaching absolute zero, the stabilization of the spin's magnetic direction reached the maximum that is theoretically possible.

          </jats:p>

          <jats:p>

            <jats:italic>Science</jats:italic>

            , this issue p.

            <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="988" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252841">988</jats:related-article>

            ; see also p.

            <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="976" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254402">976</jats:related-article>

          </jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Loth2012,

title = {Bistability in Atomic-Scale Antiferromagnets},

author = {Sebastian Loth and Susanne Baumann and Christopher P. Lutz and D. M. Eigler and Andreas J. Heinrich},

doi = {10.1126/science.1214131},

issn = {1095-9203},

year  = {2012},

date = {2012-01-13},

journal = {Science},

volume = {335},

number = {6065},

pages = {196--199},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {Structured Memories

          

            High-density magnetic memory is generally produced by using ferromagnetic materials. As the density increases and the memory elements become closer together, stray fields can result in cross-talk and a corruption of the stored information. Antiferromagetic structures, however, are expected to be relatively insensitive to magnetic fields and so should, in principle, allow the elements to be packed in even closer.

            

              Loth

              et al.

            

            (p.

            196

            ) carried out low-temperature experiments to construct antiferromagnetic structures atom by atom. Electrical switching of the magnetic states was observed, and data could be robustly stored on the structure for several hours, albeit at low temperature.

          },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ternes2008,

title = {The Force Needed to Move an Atom on a Surface},

author = {Markus Ternes and Christopher P. Lutz and Cyrus F. Hirjibehedin and Franz J. Giessibl and Andreas J. Heinrich},

doi = {10.1126/science.1150288},

issn = {1095-9203},

year  = {2008},

date = {2008-02-22},

journal = {Science},

volume = {319},

number = {5866},

pages = {1066--1069},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {Manipulation of individual atoms and molecules by scanning probe microscopy offers the ability of controlled assembly at the single-atom scale. However, the driving forces behind atomic manipulation have not yet been measured. We used an atomic force microscope to measure the vertical and lateral forces exerted on individual adsorbed atoms or molecules by the probe tip. We found that the force that it takes to move an atom depends strongly on the adsorbate and the surface. Our results indicate that for moving metal atoms on metal surfaces, the lateral force component plays the dominant role. Furthermore, measuring spatial maps of the forces during manipulation yielded the full potential energy landscape of the tip-sample interaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hirjibehedin2006,

title = {Spin Coupling in Engineered Atomic Structures},

author = {Cyrus F. Hirjibehedin and Christopher P. Lutz and Andreas J. Heinrich},

doi = {10.1126/science.1125398},

issn = {1095-9203},

year  = {2006},

date = {2006-05-19},

journal = {Science},

volume = {312},

number = {5776},

pages = {1021--1024},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {We used a scanning tunneling microscope to probe the interactions between spins in individual atomic-scale magnetic structures. Linear chains of 1 to 10 manganese atoms were assembled one atom at a time on a thin insulating layer, and the spin excitation spectra of these structures were measured with inelastic electron tunneling spectroscopy. We observed excitations of the coupled atomic spins that can change both the total spin and its orientation. Comparison with a model spin-interaction Hamiltonian yielded the collective spin configuration and the strength of the coupling between the atomic spins.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Heinrich2004,

title = {Single-Atom Spin-Flip Spectroscopy},

author = {A. J. Heinrich and J. A. Gupta and C. P. Lutz and D. M. Eigler},

doi = {10.1126/science.1101077},

issn = {1095-9203},

year  = {2004},

date = {2004-10-15},

journal = {Science},

volume = {306},

number = {5695},

pages = {466--469},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {

            We demonstrate the ability to measure the energy required to flip the spin of single adsorbed atoms. A low-temperature, high–magnetic field scanning tunneling microscope was used to measure the spin excitation spectra of individual manganese atoms adsorbed on Al

            2

            O

            3

            islands on a NiAl surface. We find pronounced variations of the spin-flip spectra for manganese atoms in different local environments.

          },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Heinrich2002,

title = {Molecule Cascades},

author = {A. J. Heinrich and C. P. Lutz and J. A. Gupta and D. M. Eigler},

doi = {10.1126/science.1076768},

issn = {1095-9203},

year  = {2002},

date = {2002-11-15},

journal = {Science},

volume = {298},

number = {5597},

pages = {1381--1387},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {Carbon monoxide molecules were arranged in atomically precise configurations, which we call “molecule cascades,” where the motion of one molecule causes the subsequent motion of another, and so on in a cascade of motion similar to a row of toppling dominoes. Isotopically pure cascades were assembled on a copper (111) surface with a low-temperature scanning tunneling microscope. The hopping rate of carbon monoxide molecules in cascades was found to be independent of temperature below 6 kelvin and to exhibit a pronounced isotope effect, hallmarks of a quantum tunneling process. At higher temperatures, we observed a thermally activated hopping rate with an anomalously low Arrhenius prefactor that we interpret as tunneling from excited vibrational states. We present a cascade-based computation scheme that has all of the devices and interconnects required for the one-time computation of an arbitrary logic function. Logic gates and other devices were implemented by engineered arrangements of molecules at the intersections of cascades. We demonstrate a three-input sorter that uses several AND gates and OR gates, as well as the crossover and fan-out units needed to connect them.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}