Hofmann, Phillip

Keywords

Electronic structure
Angle-resolved photoemission spectroscopy
Synchrotron radiation
Ultrafast electron dynamics

Head of Phillips Hofmann's research group

Professor Philip Hofmann

Electronic properties and electron dynamics in quantum materials

Our group is using powerful analytical tools (synchrotron radiation-based photoelectron spectroscopy, time-resolved photoelectron spectroscopy, nano-scale transport measurements and scanning tunnelling microscopy) to study the electronic properties and electron dynamics in quantum materials. We are mostly working with the surfaces of semimetals, topological insulators and with novel two-dimensional materials such as graphene or single-layer transition metal dichalcogenides.

Recent publications

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Gammelgaard, L., Bøggild, P., Wells, J., Handrup, K., Hofmann, P., Balslev, M. B., Hansen, J. E. & Petersen, P. R. E. (2008). A complementary metal-oxide-semiconductor compatible monocantilever 12-point probe for conductivity measurements on the nanoscale. Applied Physics Letters, 93, 093104.

Silkin, V. M., Pitarke, J. M., Chulkov, E. V., Diaconescu, B., Pohl, K., Vattuone, L., Savio, L., Hofmann, P., Farías, D., Rocca, M. & Echenique, P. M. (2008). Band structure effects on the Be(0001) acoustic surface plasmon energy dispersion. Physica Status Solidi. A: Applications and Materials Science, 1307-1311.

Hofmann, P. (2008). Solid State Physics. (1 ed.) Wiley-VCH.

Wells, J., Kallehauge, J. & Hofmann, P. (2008). Surface-sensitive conductance measurements on clean and stepped semiconductor surfaces: Numerical simulations of four point probe measurements. Surface Science, 602, 1742-1749.

Wells, J., Handrup, K., Kallehauge, J., Gammelgaard, L., Bøggild, P., Balslev, M. B., Hansen, J. E., Petersen, P. R. E. & Hofmann, P. (2008). The conductivity of Bi(111) investigated with nanoscale four point probes. Journal of Applied Physics, 104, 053717.

Wells, J., Kallehauge, J. & Hofmann, P. (2008). Thermal switching of the electrical conductivity of Si(111)(root 3 x root 3)Ag due to a surface phase transition. Journal of Physics: Condensed Matter, 20(33).

Dou, W., Dandan, G., Song, F., Li, N., Zhang, H., Li, H., He, P., Chen, H., Shining, B. & Hofmann, P. (2008). Valence electronic properties of n-channel organic materials based on fluorinated derivatives of perylene diimides. Journal of Chemical Physics, 128(24), 244711.

Chien, T. Y., Rienks, E., Jensen, M. F., Hofmann, P. & Plummer, E. W. (2009). Anisotropic electron-phonon coupling on a two-dimensional circular Fermi contour. Physical Review B, 80, 241416. https://doi.org/10.1103/PhysRevB.80.241416

Balog, R., Jørgensen, B., Wells, J., Lægsgaard, E., Hofmann, P., Besenbacher, F. & Hornekær, L. (2009). Atomic hydrogen adsorbate structures on graphene. Journal of the American Chemical Society, 131(25), 8744. https://doi.org/10.1021/ja902714h

Song, F., Wells, J., Handrup, K., Li, Z., Bao, S. N., Schulte, K., Ahola-Tuomi, M., Mayor, L. C., Swarbrick, J. C., Perkins, E., Gammelgaard, L. & Hofmann, P. (2009). Direct measurement of electrical conductance through a self-assembled molecular layer. Nature Nanotechnology, 373-376. https://doi.org/10.1038/NNANO.2009.82

Hofmann, P., Sklyadneva, I. Y., Rienks, E. & Chulkov, E. V. (2009). Electron-phonon coupling at surfaces and interfaces. New Journal of Physics, 11, 125005. https://doi.org/10.1088/1367-2630/11/12/125005

Moosburger-Will, J., Kündel, J., Klemm, M., Horn, S., Hofmann, P., Schwingenschlögl, U. & Eyert, V. (2009). Fermi surface of MoO2 studied by angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations. Physical Review B, 79(11), 115113-. https://doi.org/10.1103/PhysRevB.79.115113

Nechaev, I. A., Jensen, M. F., Rienks, E., Silkin, V. M., Echenique, P. M., Chulkov, E. V. & Hofmann, P. (2009). Hole dynamics in a two-dimensional spin-orbit coupled electron system: Theoreticaland experimental study of the Au(111) surface state. Physical Review B, 80, 113402. https://doi.org/10.1103/PhysRevB.80.113402

Wells, J., Dil, J. H., Meier, F., Lobo-Checa, J., Petrov, V. N., Osterwalder, J., Ugeda, M. M., Fernandez-Torrente, I., Pascual, J. I., Rienks, E., Jensen, M. F. & Hofmann, P. (2009). Nondegenerate metallic States on Bi(114): A One-Dimensional Topological Metal. Physical Review Letters, 102, 096802. https://doi.org/10.1103/PhysRevLett.102.096802

Song, F., Mao, H., Guan, D., Dou, W., Zhang, H., Li, H., He, P., Hofmann, P. & Bao, S. (2009). Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110). Journal of Physics: Condensed Matter, 21, 355005. https://doi.org/10.1088/0953-8984/21/35/355005

Hofmann, P. & Wells, J. (2009). Surface-sensitive conductance measurements. Journal of Physics: Condensed Matter, 21, 013003. https://doi.org/10.1088/0953-8984/21/1/013003

Lizzit, S., Baraldi, A., Grütter, C., Bilgram, J. H. & Hofmann, P. (2009). The surface phase transition and low-temperature phase of a-Ga(010) studiedby SPA-LEED. Surface Science, 603, 3222-3226. https://doi.org/10.1016/j.susc.2009.09.006

Lizzit, S., Zampieri, G., Petaccia, L., Larciprete, R., Lacovig, P., Rienks, E. D. L., Bihlmayer, G., Baraldi, A. & Hofmann, P. (2010). Band dispersion in the deep 1s core levelof graphene. Nature Physics, 6(5), 345-349. https://doi.org/10.1038/NPHYS1615

Balog, R., Jørgensen, B., Nilsson, L., Andersen, M., Rienks, E., Bianchi, M., Fanetti, M., Lægsgaard, E., Baraldi, A., Lizzit, S., Sljivancanin, Z., Besenbacher, F., Hammer, B., Pedersen, T. G., Hofmann, P. & Hornekær, L. (2010). Bandgap opening in graphene induced by patterned hydrogen adsorption. Nature Materials, 9, 315-319. https://doi.org/10.1038/NMAT2710

Bianchi, M., Guan, D., Bao, S., Mi, J., Iversen, B. B., King, P. D. C. & Hofmann, P. (2010). Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi₂Se₃. Nature Communications, 1(8), 128. https://doi.org/10.1038/ncomms1131

Bianchi, M., Rienks, E., Lizzit, S., Baraldi, A., Balog, R., Hornekær, L. & Hofmann, P. (2010). Electron-phonon coupling in potassium-doped graphene: Angle-resolved photoemission spectroscopy. Physical Review B, 81(4), 041403. https://doi.org/10.1103/PhysRevB.81.041403

Sun, J., Wang, J., Wells, J., Koroteev, Y. M., Bihlmayer, G., Chulkov, E. V., Hofmann, P. & Pohl, K. (2010). Structure and oscillatory multilayer relaxation of the bismuth (100) surface. New Journal of Physics, 12, 063016. https://doi.org/10.1088/1367-2630/12/6/063016

King, P. D. C., Veal, T. D., McConville, C. F., Zúñiga-Pérez, J., Muñoz-Sanjosé, V., Hopkinson, M., Rienks, E., Jensen, M. F. & Hofmann, P. (2010). Surface Band-Gap Narrowing in Quantized Electron Accumulation Layers. Physical Review Letters, 104(25), 256803. https://doi.org/10.1103/PhysRevLett.104.256803

King, P. D. C., Hatch, R., Bianchi, M., Ovsyannikov, R., Lupulescu, C., Landolt, G., Slomski, B., Dil, J. H., Guan, D., Mi, J., Rienks, E. D. L., Fink, J., Lindblad, A., Svensson, S., Bao, S., Balakrishnan, G., Iversen, B. B., Osterwalder, J., Eberhardt, W. ... Hofmann, P. (2011). Large Tunable Rashba Spin Splitting of a Two-Dimensional Electron Gas in Bi₂Se₃. Physical Review Letters, 107(9), 096802-1 - 096802-5. https://doi.org/10.1103/PhysRevLett.107.096802

Bianchi, M., Hatch, R. C., Hofmann, P., Mi, J. & Iversen, B. B. (2011). Simultaneous Quantization of Bulk Conduction and Valence States through Adsorption of Nonmagnetic Impurities on Bi₂Se₃. Physical Review Letters, 107(8), 086802-1 - 086802-4. https://doi.org/10.1103/PhysRevLett.107.086802

Hatch, R. C., Bianchi, M., Guan, D., Shining, B., Iversen, B. B., Nilsson, L., Hornekær, L. & Hofmann, P. (2011). Stability of the Bi2Se3(111) topological state: Electron-phonon and electron-defect scattering. Physical Review B, 83, 241303. https://doi.org/10.1103/PhysRevB.83.241303

Guan, D., Bianchi, M., Bao, S., Perkins, E. W., Meier, F., Dil, J. H., Osterwalder, J. & Hofmann, P. (2011). Strongly enhanced electron-phonon coupling in the Rashba-split state of the Bi/Ag(111) surface alloy. Physical Review B, 83(15), 155451. https://doi.org/10.1103/PhysRevB.83.155451

Song, F., Gammelgaard, L., Hofmann, P. & Wells, J. W. (2011). Suppression of the Ag/Si surface conductivity transition temperature by organic adsorbates. Applied Physics Letters, 98(5), 052106. https://doi.org/10.1063/1.3543853

Pozzo, M., Alfè, D., Lacovig, P., Hofmann, P., Lizzit, S. & Baraldi, A. (2011). Thermal Expansion of Supported and Freestanding Graphene: Lattice Constant versus Interatomic Distance. Physical Review Letters, 106(13), 135501. https://doi.org/10.1103/PhysRevLett.106.135501

Bahramy, M. S., King, P. D. C., de la Torre, A., Chang, J., Shi, M., Patthey, L., Balakrishnan, G., Hofmann, P., Arita, R., Nagaosa, N. & Baumberger, F. (2012). Emergent quantum confinement at topological insulator surfaces. Nature Communications, 3(1159), 1-7. https://doi.org/10.1038/ncomms2162

Nilsson, L., Andersen, M., Balog, R., Lægsgaard, E., Hofmann, P., Besenbacher, F., Hammer, B., Stensgaard, I. & Hornekær, L. (2012). Graphene Coatings: Probing the Limits of the One Atom Thick Protection Layer. A C S Nano, 6(11), 10258–10266. https://doi.org/10.1021/nn3040588

Ulstrup, S., Bianchi, M., Guan, D., Baraldi, A., Alfè, D., Hornekær, L. & Hofmann, P. (2012). High-temperature behavior of supported graphene: Electron-phonon coupling and substrate-induced doping. Physical Review B, 86. https://doi.org/10.1103/PhysRevB.86.161402

Honolka, J., Khajetoorians, A. A., Sessi, V., Wehling, T. O., Stepanow, S., Mi, J., Iversen, B. B., Schlenk, T., Wiebe, J., Brookes, N. B., Lichtenstein, A. I., Hofmann, P., Kern, K. & Wiesendanger, R. (2012). In-Plane Magnetic Anisotropy of Fe Atoms on Bi₂Se₃ (111). Physical Review Letters, 108, 256811. https://doi.org/10.1103/PhysRevLett.108.256811

Larciprete, R., Ulstrup, S., Lacovig, P., Dalmiglio, M., Bianchi, M., Mazzola, F., Hornekær, L., Orlando, F., Baraldi, A., Hofmann, P. & Lizzit, S. (2012). Oxygen Switching of the Epitaxial Graphene-Metal Interaction. A C S Nano, 6(11), 9551–9558. https://doi.org/10.1021/nn302729j

Bianchi, M., Hatch, R., Li, Z., Hofmann, P., Song, F., Mi, J., Iversen, B. B., El-Fattah, Z. M. A., Löptien, P., Zhou, L., Khajetoorians, A. A., Weibe, J., Wiesendanger, R. & Wells, J. W. (2012). Robust Surface Doping of Bi₂Se₃ by Rubidium Intercalation. A C S Nano, 6(8), 7009-7015. https://doi.org/10.1021/nn3021822

Bianchi, M., Guan, D., Strózecka, A., Haldan Voetmann, C., Bao, S., Pascual, J. I., Eiguren, A. & Hofmann, P. (2012). Surface states on a topologically nontrivial semimetal: The case of Sb(110). Physical Review B, 85, 155431. https://doi.org/10.1103/PhysRevB.85.155431

Bianchi, M., Hatch, R., Guan, D., Planke, T., Mi, J., Iversen, B. B. & Hofmann, P. (2012). The electronic structure of clean and adsorbate-covered Bi2Se3: an angle-resolved photoemission study. Semiconductor Science and Technology, 27. https://doi.org/10.1088/0268-1242/27/12/124001

Lizzit, S., Larciprete, R., Lacovig, P., Dalmiglio, M., Orlando, F., Baraldi, A., Gammelgaard, L., Barreto, L., Bianchi, M., Perkins, E. & Hofmann, P. (2012). Transfer-Free Electrical Insulation of Epitaxial Graphene from its Metal Substrate. Nano Letters, 12, 4503−4507. https://doi.org/10.1021/nl301614j

Strózecka, A., Eiguren, A., Bianchi, M., Guan, D., Haldan Voetmann, C., Bao, S., Hofmann, P. & Pascual, J. (2012). Unconventional spin texture of a topologically nontrivial semimetal Sb(110). New Journal of Physics, 14, 103026. https://doi.org/10.1088/1367-2630/14/10/103026

Hofmann, P. (2013). Bilayer graphene: A little twist with big consequences. Nature Materials, 12(10), 874-875. https://doi.org/10.1038/nmat3764

Schlenk, T., Bianchi, M., Koleini, M., Eich, A., Pietzsch, O., O. Wehling, T., Frauenheim, T., Balatsky, A., -L. Mi, J., Iversen, B. B., Wiebe, J., A. Khajetoorians, A., Hofmann, P. & Wiesendanger, R. (2013). Controllable magnetic doping of the surface state of a topological insulator. Physical Review Letters, 110(12), 126804. https://doi.org/10.1103/PhysRevLett.110.126804

Balog, R., Andersen, M., Jørgensen, B., Sljivancanin, Z., Hammer, B., Baraldi, A., Larciprete, R., Hofmann, P., Hornekær, L. & Lizzit, S. (2013). Controlling Hydrogenation of Graphene on Ir(111). A C S Nano, 7(5), 3823–3832. https://doi.org/10.1021/nn400780x

Barreto, L., Perkins, E., Johannsen, J., Ulstrup, S., Fromm, F., Raidel, C., Seyller, T. & Hofmann, P. (2013). Detecting the local transport properties and the dimensionality of transport of epitaxial graphene by a multi-point probe approach. Applied Physics Letters, 102(3). https://doi.org/10.1063/1.4789508

Miwa, J., Hofmann, P., Simmons, M. Y. & Wells, J. (2013). Direct Measurement of the Band Structure of a Buried Two-Dimensional Electron Gas. Physical Review Letters, 110, 136801. https://doi.org/10.1103/PhysRevLett.110.136801

Johannsen, J. C., Ulstrup, S., Cilento, F., Crepaldi, A., Zacchigna, M., Cacho, C., Turcu, I. C. E., Springate, E., Fromm, F., Raidel, C., Seyller, T., Parmigiani, F., Grioni, M. & Hofmann, P. (2013). Direct View of Hot Carrier Dynamics in Graphene. Physical Review Letters, 111, 027403-1-027403-5. https://doi.org/10.1103/PhysRevLett.111.027403

Ulstrup, S., Nilsson, L., Miwa, J. A., Balog, R., Bianchi, M., Hornekær, L. & Hofmann, P. (2013). Electronic structure of graphene on a reconstructed Pt(100) surface: Hydrogen adsorption, doping, and band gaps. Physical Review B - Condensed Matter and Materials Physics, 88(12). https://doi.org/10.1103/PhysRevB.88.125425

Christian Johannsen, J., Ulstrup, S., Bianchi, M., Hatch, R., Guan, D., Mazzola, F., Hornekær, L., Fromm, F., Raidel, C., Seyller, T. & Hofmann, P. (2013). Electron-phonon coupling in quasi free-standing graphene. Journal of Physics: Condensed Matter, 25, 094001. https://doi.org/10.1088/0953-8984/25/9/094001

Barreto, L., Bianchi, M., Guan, D., Hatch, R., Mi, J., Iversen, B. B. & Hofmann, P. (2013). Electron–phonon coupling in the two-dimensional electron gas on Bi₂Se₃. Physica Status Solidi. Rapid Research Letters, 7(1-2), 136-138. https://doi.org/10.1002/pssr.201206407

Nechaev, I. A., Hatch, R. C., Bianchi, M., Guan, D., Friedrich, C., Aguilera, I., Mi, J. L., Iversen, B. B., Blügel, S., Hofmann, P. & Chulkov, E. V. (2013). Evidence for a direct band gap in the topological insulator Bi₂Se₃ from theory and experiment. Physical Review B, 87(12), Article 121111. https://doi.org/10.1103/PhysRevB.87.121111

Leuenberger, D., Yanagisawa, H., Roth, S., Dil, J. H., Wells, J. W., Hofmann, P., Osterwalder, J. & Hengsberger, M. (2013). Excitation of coherent phonons in the one-dimensional Bi(114) surface. Physical Review Letters, 110(13), Article 136806. https://doi.org/10.1103/PhysRevLett.110.136806

Displaying results 51 to 100 out of 250

Revised 08.12.2025

Lise Refstrup Linnebjerg Pedersen