Publications (13)
Terahertz Magneto-optical investigation of quadrupolar spin-lattice effects in magnetically frustrated Tb2Ti2O7
K. Amelin, Y. Alexanian, U. Nagel +9
The significance of spin-lattice coupling in the phase diagram of the quantum spin-icepyrochlore Tb2Ti2O7 has been a topic of debate for some time. Here, we focus on the aspect of…
Duality and domain wall dynamics in a twisted Kitaev chain
C. M. Morris, Nisheeta Desai, J. Viirok +9
The Ising chain in transverse field is a paradigmatic model for a host of physical phenomena, including spontaneous symmetry breaking, topological defects, quantum criticality, and…
New Far Infrared Vibrational Mode in Zn Doped CuGeO3
J. J. McGuire, T. Room, T. E. Mason +4
We report on far infrared measurements on Zn and Si doped crystals of the spin-Peierls compound CuGeO3. Zn doping has the effect of introducing several new absorption lines, polari…
Optical spectroscopy of superconducting Ba{0.55}K{0.45}Fe2As2: evidence for strong coupling to low energy bosons
J. Yang, D. Huvonen, U. Nagel +6
Optical spectroscopy on single crystals of the new iron arsenide superconductor Ba{0.55}K{0.45}Fe2As2 shows that the infrared spectrum consists of two major components: a strong me…
Incoherent Interplane Conductivity of kappa-(BEDT-TTF)2Cu[N(CN)2]Br
J. J. McGuire, T. Room, A. Pronin +4
The interplane optical spectrum of the organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br was investigated in the frequency range from 40 to 40,000 cm-1. The optical conductivity…
Far infrared study of the two dimensional dimer spin system SrCu_2(BO_3)_2
T. Room, U. Nagel, E. Lippmaa +3
Using far-infrared spectroscopy in magnetic fields up to 12T we have studied a two-dimensional dimer spin gap system SrCu_2(BO_3)_2. We found several infrared active modes in the d…
Optical signature of sub-gap absorption in the superconducting state of Ba(Fe,Co)2As2
R. P. S. M. Lobo, Y. M. Dai, U. Nagel +5
The optical conductivity of Ba(FeCo)As shows a clear signature of the superconducting gap, but a simple -wave description fails in accounting for the l…
Infrared spectroscopy of endohedral water in C
A. Shugai, U. Nagel, Y. Murata +7
Infrared absorption spectroscopy study of endohedral water molecule in a solid mixture of HO@C and C was carried out at liquid helium temperature. From the evolut…
Optical diode effect in the room-temperature multiferroic BiFeO$_3
I. Kezsmarki, U. Nagel, S. Bordacs +5
Multiferroics permit the magnetic control of the electric polarization and electric control of the magnetization. These static magnetoelectric (ME) effects are of enormous interest…
Infrared and optical properties of pure and cobalt-doped LuNi_2B_2C
M. Windt, J. J. McGuire, T. Room +4
We present optical conductivity data for Lu(NiCo)BC over a wide range of frequencies and temperatures for x=0 and x=0.09. Both materials show evidence of being…
Suppression of the charge-density-wave state in Sr_14Cu_24O_41 by calcium doping
T. Vuletic, B. Korin-Hamzic, S. Tomic +7
The charge response in the spin chain/ladder compound Sr_14-xCa_xCu_24O_41 is characterized by DC resistivity, low-frequency dielectric spectroscopy and optical spectroscopy. We id…
Far-infrared signature of the superconducting gap in intercalated graphite CaC6
U. Nagel, D. Huvonen, E. Joon +3
Terahertz reflectance spectra of the Ca-intercalated graphite CaC6 reveal a superconducting gap below 11K. The gap signature lacks a sharp onset to full reflectivity at 2Delta, but…
Simultaneously Magnetic- and Electric-dipole Active Spin Excitations Govern the Static Magnetoelectric Effect in Multiferroic Materials
D. Szaller, S. Bordacs, V. Kocsis +3
We derive a sum rule to demonstrate that the static magnetoelectric (ME) effect is governed by optical transitions that are simultaneously excited via the electric and magnetic com…