Hofmann, Phillip

Philip Hofmann

Professor

M philip@phys.au.dk
H 1520, 323
P +4587155612
P +4587155612

Keywords

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

Head of Phillips Hofmann's research group

Professor Philip Hofmann

Website

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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Mazzola, F., Wells, J., Yakimova, R., Ulstrup, S., Miwa, J., Balog, R., Bianchi, M., Leandersson, M., Adell, J., Hofmann, P. & Balasubramanian, T. (2013). Kinks in the σ Band of Graphene Induced by Electron-Phonon Coupling. Physical Review Letters, 111. https://doi.org/10.1103/PhysRevLett.111.216806

Mi, J.-L., Bremholm, M., Bianchi, M., Borup, K. A., Johnsen, S., Søndergaard, M., Guan, D., Hatch, R., Hofmann, P. & Iversen, B. B. (2013). Phase Separation and Bulk p-n Transition in Single Crystals of Bi₂Te₂Se Topological Insulator. Advanced Materials, 25(6), 889-893. https://doi.org/10.1002/adma.201203542

Perkins, E., Barreto, L., Wells, J. & Hofmann, P. (2013). Surface-sensitive conductivity measurement using a micro multi-point probe approach. Review of Scientific Instruments, 84(3), 033901. https://doi.org/10.1063/1.4793376

dos Reis, D. D., Barreto, L., Bianchi, M., Silva Ribeiro, G. A., Soares, E. A., Simões e Silva, W., Eustáquio de Carvalho, V., Rawle, J., Hoesch, M., Nicklin, C., Fernandes, W. P., Mi, J., Iversen, B. B. & Hofmann, P. (2013). Surface structure of Bi₂Se₃(111) determined by low-energy electron diffraction and surface x-ray diffraction. Physical Review B, 88, Article 041404. https://doi.org/10.1103/PhysRevB.88.041404

Zhu, X.-G., Stensgaard, M., Barreto, L., Silva, W. S. E., Ulstrup, S., Michiardi, M., Bianchi, M., Dendzik, M. & Hofmann, P. (2013). Three Dirac points on the (110) surface of the topological insulator Bi_1-xSb_x. New Journal of Physics, 15, Article 103011. https://doi.org/10.1088/1367-2630/15/10/103011

Omiciuolo, L., Hernández, E. R., Miniussi, E., Orlando, F., Lacovig, P., Lizzit, S., Menteş, T. O., Locatelli, A., Larciprete, R., Bianchi, M., Ulstrup, S., Hofmann, P., Alfè, D. & Baraldi, A. (2014). Bottom-up approach for the low-cost synthesis of graphene-alumina nanosheet interfaces using bimetallic alloys. Nature Communications, 5, Article 5062. https://doi.org/10.1038/ncomms6062

Michiardi, M., Aguilera, I., Bianchi, M., Eustáquio de Carvalho, V., Orlando Ladeira, L., Gomes Teixeira, N., Avellar Soares, E., Friedrich, C., Blügel, S. & Hofmann, P. (2014). Bulk band structure of Bi2Te3. Physical Review B, 90, Article 075105. https://doi.org/10.1103/PhysRevB.90.075105

Riley, J. M., Mazzola, F., Dendzik, M., Michiardi, M., Takayama, T., Bawden, L., Granerod, C., Leandersson, M., Balasubramanian, T., Hoesch, M., Kim, T. K., Takagi, H., Meevasana, W., Hofmann, P., Bahramy, M. S., Wells, J. W. & King, P. D. C. (2014). Direct observation of spin-polarized bulk bands in an inversion-symmetric semiconductor. Nature Physics, 10(11), 835-839. https://doi.org/10.1038/NPHYS3105

Ulstrup, S., Johannsen, J. C., Grioni, M. & Hofmann, P. (2014). Extracting the temperature of hot carriers in time- and angle-resolved photoemission. Review of Scientific Instruments, Article 013907. https://doi.org/10.1063/1.4863322

Eich, A., Michiardi, M., Bihlmayer, G., Zhu, X.-G., Mi, J., B. Iversen, B., Wiesendanger, R., Hofmann, P., A. Khajetoorians, A. & Wiebe, J. (2014). Intra- and Interband Electron Scattering in a Hybrid Topological Insulator: Bismuth Bilayer on Bi₂Se₃. Physical Review B, 90, Article 155414. https://doi.org/10.1103/PhysRevB.90.155414

Löptien, P., Zhou, L., Wiebe, J., Khajetoorians, A. A., Mi, J., Iversen, B. B., Hofmann, P. & Wiesendanger, R. (2014). Screening and atomic-scale engineering of the potential at a topological insulator surface. Physical Review B, 89, Article 085401. https://doi.org/10.1103/PhysRevB.89.085401

Ulstrup, S., Andersen, M., Bianchi, M., Barreto, L., Hammer, B., Hornekær, L. & Hofmann, P. (2014). Sequential Oxygen and Alkali Intercalation of Epitaxial Graphene on Ir(111): Enhanced Many-Body Effects and Formation of pn-interfaces. 2D materials, 1, Article 025002.

Barreto, L., Kühnemund, L., Edler, F., Tegenkamp, C., Mi, J., Bremholm, M., Brummerstedt Iversen, B., Frydendahl, C., Bianchi, M. & Hofmann, P. (2014). Surface-Dominated Transport on a Bulk Topological Insulator. Nano Letters, 14(7), 3755-3760. https://doi.org/10.1021/nl501489m

Zhu, X.-G. & Hofmann, P. (2014). Topological surface states on Bi$_{1-x}$Sb$_x$: Dependence on surface orientation, surface termination and stability. Physical Review B, 89, Article 125402. https://doi.org/10.1103/PhysRevB.89.125402

Ulstrup, S., Johannsen, J. C., Cilento, F., Miwa, J. A., Crepaldi, A., Zacchigna, M., Cacho, C., Chapman, R., Springate, E., Mammadov, S., Fromm, F., Raidel, C., Seyller, T., Parmigiani, F., Grioni, M., King, P. D. C. & Hofmann, P. (2014). Ultrafast dynamics of massive dirac fermions in bilayer graphene. Physical Review Letters, 112(25), 257401.

Ram, S. K., Rizzoli, R., Desta, D., Jeppesen, B. R., Bellettato, M., Samatov, I., Tsao, Y.-C., Johannsen, S. R., Neuvonen, P. T., Pedersen, T. G., Pereira, R. N., Pedersen, K., Balling, P. & Larsen, A. N. (2015). Directly patterned TiO₂ nanostructures for efficient light harvesting in thin film solar cells. Journal of Physics D: Applied Physics, 48(36), Article 365101. https://doi.org/10.1088/0022-3727/48/36/365101

Koefoed, L., Kongsfelt, M. S., Ulstrup, S., Grubisic Cabo, A., Cassidy, A., Whelan, P. R., Bianchi, M., Dendzik, M., Pizzocchero, F., Jørgensen, B., Bøggild, P., Hornekær, L., Hofmann, P., Pedersen, S. U. & Daasbjerg, K. (2015). Electrochemical Transfer of Large-Area Single Crystal Epitaxial Graphene from Ir(111). Poster session presented at Graphene 2015, Bilbao, Spain.

Miwa, J. A., Ulstrup, S., Sorensen, S. G., Dendzik, M., Cabo, A. G., Bianchi, M., Lauritsen, J. V. & Hofmann, P. (2015). Electronic Structure of Epitaxial Single-Layer MoS2. Physical Review Letters, 114(4), Article 046802. https://doi.org/10.1103/PhysRevLett.114.046802

Koefoed, L., Kongsfelt, M., Ulstrup, S., Cabo, A. G., Cassidy, A., Whelan, P. R., Bianchi, M., Dendzik, M., Pizzocchero, F., Jørgensen, B., Bøggild, P., Hornekær, L., Hofmann, P., Pedersen, S. U. & Daasbjerg, K. (2015). Facile electrochemical transfer of large-area single crystal epitaxial graphene from Ir(111). Journal of Physics D: Applied Physics, 48(11), Article 115306. https://doi.org/10.1088/0022-3727/48/11/115306

Dendzik, M., Michiardi, M., Sanders, C., Bianchi, M., Miwa, J. A., Grønborg, S. S., Lauritsen, J. V., Bruix, A., Hammer, B. & Hofmann, P. (2015). Growth and electronic structure of epitaxial single-layer WS₂ on Au(111). Physical Review B, 92(24), Article 245442. https://doi.org/10.1103/PhysRevB.92.245442

Cabo, A. G., Miwa, J. A., Sørensen, S. G., Riley, J. M., Johannsen, J. C., Cacho, C., Alexander, O., Chapman, R. T., Springate, E., Grioni, M., Lauritsen, J. V., King, P. D. C., Hofmann, P. & Ulstrup, S. (2015). Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS₂. Nano Letters, 15(9), 5883-5887. https://doi.org/10.1021/acs.nanolett.5b01967

Bianchi, M., Song, F., Cooil, S., Monsen, A. F., Wahlstrom, E., Miwa, J. A., Rienks, E. D. L., Evans, D. A., Strozecka, A., Pascual, J. I., Leandersson, M., Balasubramanian, T., Hofmann, P. & Wells, J. W. (2015). One-dimensional spin texture of Bi(441): Quantum spin Hall properties without a topological insulator. Physical Review B, 91(16), Article 165307. https://doi.org/10.1103/PhysRevB.91.165307

Madsen, S. P., Johannsen, S. R., Jeppesen, B. R., Nygaard, J. V., Jensen, P. B., Chevallier, J., Julsgaard, B., Balling, P. & Larsen, A. N. (2015). Optimizing Plasmonically Enhanced Upconversion. Poster session presented at SiliconPV 2015, Konstanz , Germany.

Madsen, S. P., Johannsen, S. R., Jeppesen, B. R., Nygaard, J. V., Jensen, P. B., Chevallier, J., Julsgaard, B., Balling, P. & Larsen, A. N. (2015). Optimizing Plasmonically Enhanced Upconversion. Energy Procedia, 77, 478-486. https://doi.org/10.1016/j.egypro.2015.07.068

Ulstrup, S., Johannsen, J. C., Cilento, F., Crepaldi, A., Miwa, J. A., Zacchigna, M., Cacho, C., Chapman, R. T., Springate, E., Fromm, F., Raidel, C., Seyller, T., King, P. D. C., Parmigiani, F., Grioni, M. & Hofmann, P. (2015). Ramifications of optical pumping on the interpretation of time-resolved photoemission experiments on graphene. Journal of Electron Spectroscopy and Related Phenomena, 200, 340-346. https://doi.org/10.1016/j.elspec.2015.04.010

Michiardi, M., Bianchi, M., Dendzik, M., Miwa, J., Hoesch, M., Kim, T. K., Matzen, P., Mi, J., Bremholm, M., Iversen, B. B. & Hofmann, P. (2015). Strongly anisotropic spin-orbit splitting in a two-dimensional electron gas. Physical Review B Condensed Matter, 91, Article 035445. https://doi.org/10.1103/PhysRevB.91.035445

Sørensen, S. G., Ulstrup, S., Bianchi, M., Dendzik, M., Sanders, C. E., Lauritsen, J. V., Hofmann, P. & Miwa, J. A. (2015). Synthesis of Epitaxial Single-Layer MoS₂ on Au(111). Langmuir, 31(35), 9700-9706. https://doi.org/10.1021/acs.langmuir.5b02533

Johannsen, J. C., Ulstrup, S., Crepaldi, A., Cilento, F., Zacchigna, M., Miwa, J. A., Cacho, C., Chapman, R. T., Springate, E., Fromm, F., Raidel, C., Seyller, T., King, P. D. C., Parmigiani, F., Grioni, M. & Hofmann, P. (2015). Tunable Carrier Multiplication and Cooling in Graphene. Nano Letters, 15(1), 326-331. https://doi.org/10.1021/nl503614v

Ulstrup, S., Johannsen, J. C., Crepaldi, A., Cilento, F., Zacchigna, M., Cacho, C., Chapman, R. T., Springate, E., Fromm, F., Raidel, C., Seyller, T., Parmigiani, F., Grioni, M. & Hofmann, P. (2015). Ultrafast electron dynamics in epitaxial graphene investigated with time- and angle-resolved photoemission spectroscopy. Journal of Physics: Condensed Matter, 27(16), Article 164206. https://doi.org/10.1088/0953-8984/27/16/164206

Johannsen, S. R., Madsen, S. P., Jeppesen, B. R., Nygaard, J. V., Julsgaard, B., Balling, P. & Nylandsted Larsen, A. (2015). Up-conversion enhancement in Er3+ doped TiO2 through plasmonic coupling: Experiments and finite-element modeling. Applied Physics Letters, 106. https://doi.org/10.1063/1.4907415

Miwa, J. A., Dendzik, M., Sørensen, S. G., Bianchi, M., Lauritsen, J. V., Hofmann, P. & Ulstrup, S. (2015). Van der Waals Epitaxy of Two-Dimensional MoS₂-Graphene Heterostructures in Ultrahigh Vacuum. ACS Nano, 9(6), 6502-6510. https://doi.org/10.1021/acsnano.5b02345

Eich, A., Rollfing, N., Arnold, F., Sanders, C., Ewen, P. R., Bianchi, M., Dendzik, M., Michiardi, M., Mi, J.-L., Bremholm, M., Wegner, D., Hofmann, P. & Khajetoorians, A. A. (2016). Absence of superconductivity in ultrathin layers of FeSe synthesized on a topological insulator. Physical Review B, 94(12), 125437. Article 125437. https://doi.org/10.1103/PhysRevB.94.125437

Warmuth, J., Bruix, A., Michiardi, M., Haenke, T., Bianchi, M., Wiebe, J., Wiesendanger, R., Hammer, B., Hofmann, P. & Khajetoorians, A. A. (2016). Band-gap engineering by Bi intercalation of graphene on Ir(111). Physical Review B, 93(16), Article 165437. https://doi.org/10.1103/PhysRevB.93.165437

Sanders, C. E., Dendzik, M., Ngankeu, A. S., Eich, A., Bruix, A., Bianchi, M., Miwa, J. A., Hammer, B., Khajetoorians, A. A. & Hofmann, P. (2016). Crystalline and electronic structure of single-layer TaS2. Physical Review B, 94(8), Article 081404. https://doi.org/10.1103/PhysRevB.94.081404

Salmi, Z., Koefoed, L., Jensen, B. B. E., Grubisic Cabo, A., Hofmann, P., Pedersen, S. U. & Daasbjerg, K. (2016). Electroinduced Intercalation of Tetraalkylammonium Ions at the Interface of Graphene Grown on Copper, Platinum, and Iridium. ChemElectroChem, 3(12), 2202–2211. https://doi.org/10.1002/celc.201600424

Ulstrup, S., Schueler, M., Bianchi, M., Fromm, F., Raidel, C., Seyller, T., Wehling, T. & Hofmann, P. (2016). Manifestation of nonlocal electron-electron interaction in graphene. Physical Review B, 94(8), Article 081403. https://doi.org/10.1103/PhysRevB.94.081403

Vondráček, M., Cornils, L., Minár, J., Warmuth, J., Michiardi, M., Piamonteze, C., Barreto, L., Miwa, J. A., Bianchi, M., Hofmann, P., Zhou, L., Kamlapure, A., Khajetoorians, A. A., Wiesendanger, R., Mi, J. L., Iversen, B. B., Mankovsky, S., Borek, S., Ebert, H. ... Honolka, J. (2016). Nickel: The time-reversal symmetry conserving partner of iron on a chalcogenide topological insulator. Physical Review B, 94(16), Article 161114. https://doi.org/10.1103/PhysRevB.94.161114

Desta, D., Ram, S., Rizzoli, R., Bellettato, M., Summonte, C., Jeppesen, B. R., Jensen, P. B., Tsao, Y.-C., Wiggers, H., Pereira, R. N., Balling, P. & Larsen, A. N. (2016). Novel back-reflector architecture with nanoparticle based buried light-scattering microstructures for improved solar cell performance. Nanoscale, 8(23), 12035-12046. Article 8. https://doi.org/10.1039/c6nr00259e

Eriksen, E., Desta, D., Bellettato, M., Rizzoli, R., Summonte, C., Jeppesen, B. R., Jensen, P. B., Madsen, S. P., Ram, S., Larsen, A. N. & Balling, P. (2016). Photovoltaic-Performance-Enhancing Patch with Combined Light Trapping and Spectral Upconverting Effect. EU PVSEC Conference Proceedings, 66-68. https://doi.org/10.4229/EUPVSEC20162016-1CO.9.2

Lakhotiya, H., Nazir, A., Madsen, S. P., Christiansen, J., Eriksen, E., Vester-Petersen, J., Johannsen, S. R., Jeppesen, B. R., Balling, P., Larsen, A. N. & Julsgaard, B. (2016). Plasmonically enhanced upconversion of 1500 nm light via trivalent Er in a TiO2 matrix. Applied Physics Letters, 109(26), Article 263102. https://doi.org/10.1063/1.4972785

Dendzik, M., Bianchi, M., Michiardi, M., Sanders, C. E. & Hofmann, P. (2016). Reconstruction-induced trefoil knot Fermi contour of Au(111). Physical Review B, 94(20), Article 201401. https://doi.org/10.1103/PhysRevB.94.201401

Samatov, I., Jeppesen, B. R., Larsen, A. N. & Ram, S. (2016). Room-temperature rf-magnetron sputter-deposited W-doped indium oxide: Decoupling the influence of W dopant and O vacancies on the film properties. Applied Physics A: Materials Science & Processing, 122(4), 1-10. Article 122:458. https://doi.org/10.1007/s00339-016-9983-0

Bruix, A., Miwa, J., Hauptmann, N., Wegner, D., Ulstrup, S., Grønborg, S. S., Sanders, C., Dendzik, M., Grubisic Cabo, A., Bianchi, M., Lauritsen, J. V., Khajetoorians, A. A., Hammer, B. & Hofmann, P. (2016). Single-layer MoS2 on Au(111): Band gap renormalization and substrate interaction. Physical Review B, 93(16), Article 165422. https://doi.org/10.1103/PhysRevB.93.165422

Queiroz, R., Landolt, G., Muff, S., Slomski, B., Schmitt, T., Strocov, V. N., Mi, J., Iversen, B. B., Hofmann, P., Osterwalder, J., Schnyder, A. P. & Dil, J. H. (2016). Sputtering-induced reemergence of the topological surface state in Bi2Se3. Physical Review B, 93(16), Article 165409. https://doi.org/10.1103/PhysRevB.93.165409

Jørgensen, J. H., Grubisic Cabo, A., Balog, R., Hansen, L. K., Groves, M. N., Cassidy, A. M., Bruix, A., Bianchi, M., Dendzik, M., Arman, M. A., Lammich, L., Pascual, J. I., Knudsen, J., Hammer, B., Hofmann, P. & Hornekaer, L. (2016). Symmetry-Driven Band Gap Engineering in Hydrogen Functionalized Graphene. A C S Nano, 10(12), 10798-10807. https://doi.org/10.1021/acsnano.6b04671

Valiska, M., Warmuth, J., Michiardi, M., Vondracek, M., Ngankeu, A. S., Holy, V., Sechovsky, V., Springholz, G., Bianchi, M., Wiebe, J., Hofmann, P. & Honolka, J. (2016). Topological insulator homojunctions including magnetic layers: The example of n-p type (n-QLs Bi2Se3/Mn-Bi2Se3) heterostructures. Applied Physics Letters, 108(26), Article 262402. https://doi.org/10.1063/1.4954834

Ulstrup, S., Grubisic Cabo, A., Miwa, J., Riley, J. M., Grønborg, S. S., Johannsen, J. C., Cacho, C., Alexander, O., Chapman, R. T., Springate, E., Bianchi, M., Dendzik, M., Lauritsen, J. V., King, P. D. C. & Hofmann, P. (2016). Ultrafast Band Structure Control of a Two-Dimensional Heterostructure. A C S Nano, 10(6), 6315-6322. https://doi.org/10.1021/acsnano.6b02622

Ram, S. K., Desta, D., Rizzoli, R., Bellettato, M., Lyckegaard, F., Jensen, P. B., Jeppesen, B. R., Chevallier, J., Summonte, C., Larsen, A. N. & Balling, P. (2017). Combining light-harvesting with detachability in high-efficiency thin-film silicon solar cells. Nanoscale, 9(21), 7169-7178. https://doi.org/10.1039/c7nr00658f

Ram, S. K., Desta, D., Rizzoli, R., Falcao, B. P., Eriksen, E. H., Bellettato, M., Jeppesen, B. R., Jensen, P. B., Summonte, C., Pereira, R. N., Larsen, A. N. & Balling, P. (2017). Efficient light-trapping with quasi-periodic uniaxial nanowrinkles for thin-film silicon solar cells. Nano Energy, 35, 341-349. https://doi.org/10.1016/j.nanoen.2017.04.016

Tamtogl, A., Kraus, P., Avidor, N., Bremholm, M., Hedegaard, E. M. J., Iversen, B. B., Bianchi, M., Hofmann, P., Ellis, J., Allison, W., Benedek, G. & Ernst, W. E. (2017). Electron-phonon coupling and surface Debye temperature of Bi2Te3(111) from helium atom scattering. Physical Review B, 95(19), Article 195401. https://doi.org/10.1103/PhysRevB.95.195401

Displaying results 101 to 150 out of 250

Revised 23.05.2023

Lise Refstrup Linnebjerg Pedersen