Dielectric and Optical Spectroscopy on Correlated Electron Systems

I. Kézsmárki, S. Krohns, P. Lunkenheimer

Publications

M. Winkler, L. Prodan, V. Tsurkan, P. Lunkenheimer, I. Kezsmarki, Antipolar transitions in GaNb₄Se₈ and GaTa₄Se₈, Phys. Rev. B 106, 115146 (2022) [F5]
D.M. Evans, O.G. Grendal, L. Prodan, M. Winkler, N. Winterhalter-Stocker, P. Gegenwart, S. Ghara, J. Deisenhofer, I. Kezsmarki, V. Tsurkan, Resolving structural changes and symmetry lowering in spinel FeCr2S4, Phys. Rev. B 105, 174107 (2022) [E6,F4,F5]
G. He, L. Peis, R. Stumberger, L. Prodan, V. Tsurkan, N. Unglert, L. Chioncel, I. Kézsmárki, R. Hackl, Phonon Anomalies Associated with Spin Reorientation in the Kagome Ferromagnet Fe$_3$Sn$_2$, Phys. Status Solidi B 259, 2100169 (2022) [F1,F5,F6]
M. Prinz-Zwick, T. Gimpel, K. Geirhos, S. Ghara, C. Steinbrecht, V. Tsurkan, N. Buttgen, I. Kézsmárki, Probing multiferroic order parameters and domain population via nuclear spins, Phys. Rev. B 105, 014301 (2022) [F5,F4]
A. Butykai, K. Geirhos, D. Szaller, L. F. Kiss, J. Balogh, M. Azhar, M. Garst, L. DeBeer-Schmidt, T. Waki, Y. Tabata, H. Nakamura, I. Kézsmárki, S. Bordács, Squeezing the periodicity of Néel-type magnetic modulations by enhanced Dzyaloshinskii-Moriya interaction of 4d electrons, Npj Quantum Mater. 7, 26 (2022) [F5]
S. Reschke, D. G. Farkas, A. Strinic, S. Ghara, K. Guratinder, O. Zaharko, L. Prodan, V. Tsurkan, D. Szaller, S. Bordacs, J. Deisenhofer, I. Kézsmárki, Confirming the trilinear form of the optical magnetoelectric effect in the polar honeycomb antiferromagnet Co$_2$Mo$-3$O$_8$, npj Quantum Materials 7, 1 (2022) [F5]
K. Geirhos, S. Reschke, S. Ghara, S. Krohns, P. Lunkenheimer, I. Kézsmárki, Optical, dielectric, and magnetoelectric properties of ferroelectric and antiferroelectric lacunar spinels, Phys. Status Solidi B 259, 2100160 (2022) [F5]
Lukas Puntigam, Jan Schultheiss, A. Strinic, Z. Yan, E. Bourret, M. Altthaler, D.M. Evans, D. Meier, I Kezsmarki, S. Krohns, Insulating improper ferroelectric domain walls as robust barrier layer capacitors, Journal of Applied Physics 129, 7, 074101 (2021) [F5]
Jan Schultheiss, E. Lysne, Lukas Puntigam, J. Schaab, E. Bourret, Z. Yan, S. Krohns, D. Meier, Charged Ferroelectric Domain Walls for Deterministic ac Signal Control at the Nanoscale, Nano Letters 21, 22, 9560 (2021) [F5]
M. Altthaler, E. Lysne, E. Roede, L. Prodan, V. Tsurkan, M. A. Kassem, H. Nakamura, S. Krohns, I. Kézsmárki, D. Meier, Magnetic and geometric control of spin textures in the itinerant kagome magnet Fe$_3$Sn$_2$, Phys. Rev. Research 3, 043191 (2021) [F5]
S. Ghara, K. Geirhos, L. Kuerten, P. Lunkenheimer, V. Tsurkan, M. Fiebig, I. Kézmárki, Giant conductivity of mobile non-oxide domain walls, Nat. Commun. 12, 3975 (2021) [F5]
S. Canossa, E. Ferrari, P. Sippel, J. K. H. Fischer, R. Pfattner, R. Frison, M. Masino, M. Mas-Torrent, P. Lunkenheimer, C. Rovira, A. Girlando, Tetramethylbenzidine-TetrafluoroTCNQ (TMB-TCNQF4_4$): A narrow-gap semiconducting salt with room-temperature relaxor ferroelectric behavior, J. Phys. Chem. C 125, 25816 (2021) [F5]
L. N. Alyabyeva, A. S. Prokhorov, D. A. Vinnik, V. B. Anzin, A. G. Ahmed, A. Mikheykin, P. Bednyakov, C. Kadlec, F. Kadlec, E. de Prado, J. Prokleska, P. Proschek, S. Kamba, A. V. Pronin, M. Dressel, V. A. Abalmasov, V. V. Dremov, S. Schmid, M. Savinov, P. Lunkenheimer, B. P. Gorshunov, Lead-substituted barium hexaferrite for tunable terahertz optoelectronics, NPG Asia Materials 13, 63 (2021) [F5]
Ch. Thurn, P. Eibisch, A. Ata, M. Winkler, P. Lunkenheimer, I. Kézsmárki, U. Tutsch, Y. Saito, S. Hartmann, J. Zimmermann, A.R.N. Hanna, A.T.M.N. Islam, S. Chillal, B. Lake, B. Wolf, M. Lang, Spin liquid and ferroelectricity close to a quantum critical point in PbCuTe$_2$O$_6$, Npj Quantum Mater. 6, 95 (2021) [F5]
A. Loidl, P. Lunkenheimer, V. Tsurkan, On the proximate Kitaev quantum-spin liquid alpha-RuCl$_3$: Thermodynamics, excitations and continua, J. Phys.: Condens. Matter 33, 443004 (2021) [F5]
V. Tsurkan, H.-A. Krug von Nidda, J. Deisenhofer, P. Lunkenheimer, A. Loidl, On the complexity of spinels: Magnetic, electronic, and polar ground states, Physics Reports 929, 1 (2021) [F5,F4]
A. Matavz, P. Kozelj, M. Winkler, K. Geirhos, P. Lunkenheimer, V. Bobnar, Nanostructured multiferroic Pb(Zr,Ti)O$_3$-NiFe$_2$O$_4$ thin-film composites, Thin Solid Films 732, 138740 (2021) [F5]
K. Geirhos, J. Langmann, L. Prodan, A. A. Tsirlin, A. Missiul, G. Eickerling, A. Jesche, V. Tsurkan, P. Lunkenheimer, W. Scherer, I. Kézsmárki, Cooperative cluster Jahn-Teller effect as a possible route to antiferroelectricity, Phys. Rev. Lett. 126, 187601 (2021) [F5,E6]
J. K. H. Fischer, G. D´Avino, M. Masino, F. Mezzadri, P. Lunkenheimer, Z. G. Soos, A. Girlando, Relaxor ferroelectricity in the polar M$_2$P-TCNQ charge-transfer crystal at the neutral-ionic interface, Phys. Rev. B 103, 115104 (2021) [F5]
T.S. Holstad, Trygve Raeder, D.M. Evans, Didrik Smarbraten, S. Krohns, J. Schaab, Z. Yan, E. Bourret, Antonius van Helvoort, Tor Grande, S.M. Selbach, Joshua Agar, D. Meier, Application of a long short-term memory for deconvoluting conductance contributions at charged ferroelectric domain walls, NPJ Computational Materials 6, 1, 163 (2020) [F5]
L. Kuerten, S. Krohns, P. Schoenherr, Katharina Holeczek, E. Pomjakushina, T. Lottermoser, M. Trassin, D. Meier, M. Fiebig, Local control of improper ferroelectric domains in YMnO$_3$, Phys. Rev. B 102, 9, 094108 (2020) [F5]
D. Szaller, K. Szasz, S. Bordács, J. Viirok, T. Rőőm, U. Nagel, A. Shuvaev, L. Weymann, A. Pimenov, A. A. Tsirlin, A. Jesche, L. Prodan, V. Tsurkan, I. Kézsmárki, Magnetic anisotropy and exchange paths for octahedrally and tetrahedrally coordinated Mn$^{2+}$ ions in the honeycomb multiferroic Mn$_2$Mo$_3$O$_8$, Phys. Rev. B 102, 144410 (2020) [F5,E6]
T. Rőőm, J. Viirok, L. Peedu, U. Nagel, D. G. Farkas, D. Szaller, V. Kocsis, S. Bordács, I. Kézsmárki, D. L. Kamenskyi, H. Engelkamp, M. Ozerov, D. Smirnov, J. Krzystek, K. Thirunavukkuarasu, Y. Ozaki, Y. Tomioka, T. Ito, T. Datta, R. S. Fishman, Magnetoelastic distortion of multiferroic BiFeO$_3$ in the canted antiferromagnetic state, Phys. Rev. B 102, 214410 (2020) [F5]
S. Reschke, F. Meggle, F. Mayr, V. Tsurkan, L. Prodan, H. Nakamura, J. Deisenhofer, C. A. Kuntscher, I. Kézsmárki, Lattice dynamics and electronic excitations in a large family of lacunar spinels with a breathing pyrochlore lattice structure, Phys. Rev. B. 101, 075118 (2020) [F5]
S. Reschke, A. A. Tsirlin, N. Khan, L. Prodan, V. Tsurkan, I. Kézsmárki, J. Deisenhofer, Structure, phonons, and orbital degrees of freedom in Fe$_2$Mo$_3$O$_8$, Phys. Rev. B 102, 094307 (2020) [F5,E6]
B. Csizi, S. Reschke, A. Strinic, L. Prodan, V. Tsurkan, I. Kézsmárki, J. Deisenhofer, Magnetic and vibronic terahertz excitations in Zn-doped Fe$_2$Mo$_3$O$_8$, Phys. Rev. B 102, 174407 (2020) [F5]
K. Geirhos, B. Gross, B. G. Szigeti, A. Mehlin, S. Philipp, J. S. White, R. Cubitt, S. Widmann, S. Ghara, P. Lunkenheimer, V. Tsurkan, E. Neuber, D. Ivaneyko, P. Milde, L. M. Eng, A. O. Leonov, S. Bordacs, M. Poggio, I. Kézsmárki, Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host, Npj Quantum Mater. 5, 44 (2020) [F5]
K. Geirhos, P. Lunkenheimer, M. Blankenhorn, R. Claus, Y. Matsumoto, K. Kitagawa, T. Takayama, H. Takagi, I. Kézsmárki, A. Loidl, Quantum paraelectricity in the Kitaev quantum-spin-liquid candidates H$_3$LiIr$_2$O$_6$ and D$_3$LiIr$_2$O$_6$, Phys. Rev. B 110, 184410 (2020) [F5]
Y. Okamura, S. Seki, S. Bordács, A. Butykai, V. Tsurkan, I. Kézsmárki, Y. Tokura, Microwave Directional Dichroism Resonant with Spin Excitations in the Polar Ferromagnet GaV$_4$S$_8$, Phys. Rev. Lett 122, 057202 (2019) [F5]
M. Padmanabhan, F. Sekiguchi, R. B. Versteeg, E. Slivina, V. Tsurkan, S. Bordács, I. Kézsmárki, P. H. M. van Loosdrecht, Optically Driven Collective Spin Excitations and Magnetization Dynamics in the Néel-type Skyrmion Host GaV$_4$S$_8$, Phys. Rev. Lett 122, 107203 (2019) [F5]
L. Peedu, V. Kocsis, D. Szaller, J. Viirok, U. Nagel, T. Rőőm, D. G. Farkas, S. Bordács, D. L. Kamenskyi, U. Zeitler, Y. Tokunaga, Y. Taguchi, Y. Tokura, I. Kézsmárki, Spin excitations of magnetoelectric LiNiPO$_4$ in multiple magnetic phases, Phys. Rev. B 100, 024406 (2019) [F5]
V. Kocsis, S. Bordacs, Y. Tokunaga, J. Viirok, L. Peedu, T. Rőőm, U. Nagel, Y. Taguchi, Y. Tokura, I. Kézsmárki, Magnetoelectric spectroscopy of spin excitations in LiCoPO$_4$, Phys. Rev. B 100, 155124 (2019) [F5]
T. Thomas, B. Hartmann, P. Lunkenheimer, H. Schubert, J. A. Schlueter, J. Müller, Low-Frequency Charge Carrier Dynamics in Ferroelectric kappa-(BEDT-TTF)$_2$X - A Comparative Study of X = Cu[N(CN)$_2$]Cl and X = Hg(SCN)$_2$Cl, Phys. Status Solidi B 256, 1800746 (2019) [F5]
S Krohns, P Lunkenheimer, Ferroelectric polarization in multiferroics, Phys. Sci. Rev. 4, 20190015 (2019) [F5]
S. Reschke, V. Tsurkan, S.-H. Do, K.-Y. Choi, P. Lunkenheimer, Z. Wang, A. Loidl, THz excitations in alpha-RuCl$_3$: Majorana fermions and rigid-plane shear and compression modes, Phys. Rev. B 100, 100403(R) (2019) [F5]
J. Viirok, U. Nagel, T. Rőőm, D. G. Farkas, P. Balla, D. Szaller, V. Kocsis, Y. Tokunaga, Y. Taguchi, Y. Tokura, B. Bernáth, D. L. Kamenskyi, I. Kezsmarki, S. Bordács, K. Penc, Directional dichroism in the paramagnetic state of multiferroics: A case study of infrared light absorption in Sr$_2$CoSi$_2$O$_7$ at high temperatures, Phys. Rev. B 99, 014410 (2019) [F5]
A. Ruff, Z. Wang, S. Zherlitsyn, J. Wosnitza, S. Krohns, H.-A. Krug von Nidda, P. Lunkenheimer, V. Tsurkan, A. Loidl, Multiferroic spin-superfluid and spin-supersolid phases in MnCr$_2$S$_4$, Phys. Rev. B 100, 014404 (2019) [F5,F4]
A. Ruff, P. Lunkenheimer, H.-A. Krug von Nidda, S. Widmann, A. Prokofiev, L. Svistov, A, Loidl, S Krohns, Chirality-driven ferroelectricity in LiCuVO$_4$, Npj Quantum Mater. 4, 24 (2019) [F5,F4]
D. Lang, J. Döring, T. Nörenberg, A. Butykai, I. Kézsmárki, H. Schneider, S. Winnerl, M. Helm, S Kehr, L. M. Eng, Infrared nanoscopy down to liquid helium temperatures, Rev. Sci. Instrum. 89, 033702 (2018) [F5]
V. Kocsis, K. Penc, T. Rőőm, U. Nagel, J. Vít, J. Romhányi, Y. Tokunaga, Y. Taguchi, Y. Tokura, I. Kézsmárki, S. Bordács, Identification of Antiferromagnetic Domains Via the Optical Magnetoelectric Effect, Phys. Rev. Lett. 121, 057601 (2018) [F5]
V. Kocsis, S. Bordács, L. F. Kiss, K. Ohgushi, Y. Kaneko, Y. Tokura, I. Kézsmárki, Strong magneto-optical effects in ACr$_2$O$_4$ (A=Fe,Co) spinel oxides generated by tetrahedrally coordinated transition metal ions, Phys. Rev. B 97, 125140 (2018) [F5]
F. Seifert, F. L. Kern, I. Kézsmárki, U. Rößler, D. Wolf, S. Schneider, D. Pohl, B. Büchner, A. Lubk, Cryogenic TEM Studies of Bloch and Neel Skyrmion Textures in Lacunar Spinels and Cubic Helimagnets, Microsc. Microanal. 24, 946 (2018) [F5,F4]
A. G. Kiiamov, Yu. V. Lysogorskiy, F. G. Vagizov, L. R. Tagirov, D. A. Tayurskii, Z. Seidov, H.-A. Krug von Nidda, V. Tsurkan, D. Croitori, A. Günther, F. Mayr, A. Loidl, Vibrational properties and magnetic specific heat of the covalent chain antiferromagnet RbFeSe$_2$, Phys. Rev. B 98, 214411 (2018) [F5,F4]
S. Reschke, F. Mayr, S. Widmann, H.-A. Krug von Nidda, V. Tsurkan, M. V. Eremin, S.-H. Do, K.-Y. Choi, Z. Wang, A. Loidl, Sub-gap optical response in the Kitaev spin-liquid candidate $\alpha$-RuCl$_3$, J. Phys.: Condens. Matter 30, 475604 (2018) [F5,F4]
A. Charnukha, D. Pröpper, N. D. Zhigadlo, M. Naito, M. Schmidt, Z. Wang, J. Deisenhofer, A. Loidl, B. Keimer, A. V. Boris, D. N. Basov, Intrinsic Charge Dynamics in High-\Tc AFeAs(O,F) Superconductors, Phys. Rev. Lett. 120, 087001 (2018) [F5,G1]
J. Schaab, S. H. Skjaervo, S. Krohns, X.Y. Dai, M. E. Holtz, A. Cano, M. Lilienblum, Z. Yan, E. Bourret, D. A. Muller, M. Fiebig, S. M. Selbach, D. Meier, Electrical half-wave rectification at ferroelectric domain walls, Nat. Nanotechnol. 13, 1028, 1028-1032 (2018) [F5]
T. Basu, A. Pautrat, V. Hardy, A. Loidl, S. Krohns, Magnetodielectric coupling in a Ru-based 6H-perovskite, BaNdRu$_2$O$_9$, Appl. Phys. Lett. 113, 042902, (2018) [F5]
A. Ruff, Z Li, A. Loidl, J. Schaab, M. Fiebig, A. Cano, Z. Yan, E. Bourret, J. Glaum, D. Meier, S. Krohns, Frequency dependent polarisation switching in h-ErMnO$_3$, Appl. Phys. Lett. 112, 182908, (2018) [F5]
T.S. Holstad, D.M. Evans, A. Ruff, D.R. Smĺbrĺten, J. Schaab, Ch. Tzschaschel, Z. Yan, E. Bourret, S.M. Selbach, S. Krohns, D. Meier, Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO$_3$, Phys. Rev. B 97, 085143, (2018) [F5]
K. Geirhos, S. Krohns, H. Nakamura, T. Waki, Y. Tabata, I. Kézsmárki, P. Lunkenheimer, Orbital-Order Driven Ferroelectricity and Dipolar Relaxation Dynamics in Multiferroic GaMo$_4$S$_8$, Phys. Rev. B 98, 224306 (2018) [F5]
E. Neuber, P. Milde, A. Butykai, S. Bordacs, H. Nakamura, T. Waki, Y. Tabata, K. Geirhos, P. Lunkenheimer, I. Kézmárki, P. Ondrejkovic, J. Hlinka, L. M. Eng, Architecture of nanoscale ferroelectric domains in GaMo$_4$S$_8$, J. Phys.: Condens. Matter 30, 445402 (2018) [F5]
J. K. H. Fischer, P. Lunkenheimer, C. Leva, S. M. Winter, M. Lang, C. Meziere, P. Batail, A. Loidl, R. S. Manna, Relaxation dynamics in the one-dimensional organic charge-transfer salt delta-(EDT-TTF-CONMe$_2$)$_2$Br, Phys. Rev. B 97, 235156 (2018) [F5]
E. Gati, J. K. H. Fischer, P. Lunkenheimer, D. Zielke, S. Köhler, F. Kolb, H.-A. Krug von Nidda, S.M. Winter, H. Schubert, J. A. Schlueter, H. O. Jeschke, R. Valenti, M. Lang, Evidence for electronically driven ferroelectricity in a strongly correlated dimerized BEDT-TTF molecular conductor , Phys. Rev. Lett. 120, 247601 (2018) [F5,F4]
Z. Wang, J. Wu, W. Yang, A. K. Bera, D. Kamenskyi, A.T.M. Nazmul Islam, S. Xu, J. M. Law, B. Lake, C. Wu, A. Loidl, Experimental observation of Bethe strings, Nature 554, 219 (2018) [F5]

Short Summary

In this project, we will investigate the dielectric, microwave, THz, and optical response of electronically correlated materials in a broad range of external parameters. We will search for new mechanisms leading to polar order and multiferroicity and explore the complex interplay of charge, spin, orbital, and lattice degrees of freedom. We will also focus on one-way transparency in multiferroics enabling unique optical applications. Moreover, we aim to unravel the physics of topologically protected structures like skyrmions and ferroelectric domain-wall vortex cores, both promising new functionalities for future advances in microelectronics.