Publications (31)
Magnetic and Charge Correlations in La{2-x-y}Nd_ySr_xCuO_4: Raman Scattering Study
A. Gozar, Seiki Komiya, Yoichi Ando +1
Two aspects in connection with the magnetic properties of La_{2-x-y}Nd_ySr_xCuO_4 single crystals are discussed. The first is related to long wavelength magnetic excitations in x =…
Magnetism in the 2D Limit and Interface Superconductivity in Metal-Insulator La(2-x)Sr(x)CuO(4) Superlattices
A. Suter, E. Morenzoni, T. Prokscha +6
We show, by means of low-energy muon spin rotation measurements, that few-unit-cells thick La(2)CuO(4) layers synthesized digitally by molecular beam epitaxy synthesis are antiferr…
Magnetic order in lightly doped La_{2-x}Sr_{x}CuO_{4}
A. Gozar, B. S. Dennis, G. Blumberg +2
We study long wavelength magnetic excitations in lightly doped La_{2-x}Sr_{x}CuO_{4} (x < 0.03) detwinned crystals. The lowest energy magnetic anisotropy induced gap can be underst…
Reply to Comment on:"Nonmonotonic d_{x^2-y^2} Superconducting Order Parameter in Nd_{2-x}Ce_xCuO_4"
G. Blumberg, A. Koitzsch, A. Gozar +4
We confirm that all the results of scanning SQUID, tunneling, ARPES, penetration depth and Raman experiments are consistent with a nonmonotonic d_{x^2-y^2} superconducting order pa…
Nonmonotonic d_{x^2-y^2} Superconducting Order Parameter in Nd_{2-x}Ce_xCuO_4
G. Blumberg, A. Koitzsch, A. Gozar +4
Low energy polarized electronic Raman scattering of the electron doped superconductor Nd_1.85Ce_0.15CuO_4 (T_c=22 K) has revealed a nonmonotonic d_{x^2-y^2} superconducting order p…
Crystal structure and high-field magnetism of La2CuO4
M. Reehuis, C. Ulrich, K. Prokes +6
Neutron diffraction was used to determine the crystal structure and magnetic ordering pattern of a La2CuO4 single crystal, with and without applied magnetic field. A previously unr…
Low-energy excitations around (Ï/2, Ï/2) points in the pseudogap phase of Nd_1.85Ce_0.15CuO_4
A. Koitzsch, G. Blumberg, A. Gozar +3
Polarized electronic Raman scattering from the NCCO superconductor at optimal electron doping (T_c=22 K) reveals the formation of an anisotropic pseudogap below a characteristic te…
Inhomogeneous CuO_{6} Tilt Distribution and Charge/Spin Correlations in La_{2-x-y}Nd_{y}Sr_{x}CuO$_{4} around commensurate hole concentration
A. Gozar, B. S. Dennis, T. Siegrist +2
Phononic and magnetic Raman scattering are studied in LaNdSrCuO with three doping concentrations: x ~ 1/8, y = 0; x ~ 1/8, y = 0.4; and x = 0.01, y = 0.…
Spin dynamics of Sr_14Cu_24O_41 two-leg ladder studied by Raman spectroscopy
A. Gozar, G. Blumberg, B. S. Dennis +4
The two-magnon (2M) excitation at 3000 cm-1 in Sr_14Cu_24O_41 two-leg ladder is studied by Raman scattering. A slight anisotropy of the superexchange coupling J_{\perp}/J_{||} \app…
Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets: II. Raman spectroscopy
L. Benfatto, M. B. Silva Neto, A. Gozar +5
We compare the theoretical predictions of the previous article [L. Benfatto and M. B. Silva Neto, cond-mat/0602419], with Raman spectroscopy experiments in Sr(2)CuO(2)Cl(2) and unt…
Electronic Stripe Patterns Near the Fermi Level of Tetragonal Fe(Se,S)
M. Walker, K. Scott, T. J. Boyle +13
FeSeS remains one of the most enigmatic systems of Fe-based superconductors. While much is known about the orthorhombic parent compound, FeSe, the tetragonal samples, F…
Collective density wave excitations in two-leg Sr_{14-x}Ca_xCu_{24}O_{41} ladders
A. Gozar, G. Blumberg, P. B. Littlewood +4
Raman measurements in the 1.5 - 20 cm-1 energy range were performed on single crystals of Sr_{14-x}Ca_xCu_{24}O_{41}. A quasielastic scattering peak (QEP) which softens with coolin…
Antiferromagnetism in CaCuTiO studied by magnetic Raman spectroscopy
A. Koitzsch, G. Blumberg, A. Gozar +4
For CaCuTiO -- an insulator that exhibits a giant dielectric response above 100 K -- Cu antiferromagnetic spin ordering has been investigated by magnetic…
Collective Spin and Charge Excitations in (Sr,La)_{14-x}Ca_xCu_{24}O_{41} Quantum Spin Ladders
A. Gozar, G. Blumberg
We study magnetic and electronic properties of two-leg ladder materials. We observed a two-magnon (2M) resonance which we analyze in terms of symmetry, relaxation and resonance pro…
Evolution of Superconductivity in Electron-Doped Cuprates: Magneto-Raman Spectroscopy
M. M. Qazilbash, A. Koitzsch, B. S. Dennis +5
The electron-doped cuprates Pr_{2-x}Ce_xCuO_4 and Nd_{2-x}Ce_xCuO_4 have been studied by electronic Raman spectroscopy across the entire region of the superconducting (SC) phase di…
Electronic Properties of α'-NaV_2O_5
A. Gozar, G. Blumberg
We studied electronic excitations in NaV2O5 by Raman. Three main topics are discussed. The first is related to a broad continuum of excitations found in the 200-1500 cm-1 range and…
Magnetic phase diagram of low-doped La{2-x}SrxCuO4 thin films studied by low-energy muon-spin rotation
E. Stilp, A. Suter, T. Prokscha +7
The magnetic phase diagram of La2-xSrxCuO4 thin-films grown on single-crystal LaSrAlO4 substrates has been determined by low-energy muon-spin rotation. The diagram shows the same f…
Phononic gaps in the charged incommensurate planes of Sr14Cu24O41
V. K. Thorsmolle, C. C. Homes, A. Gozar +6
The terahertz (THz) excitations in the quantum spin-ladder system Sr14Cu24O41 have been determined along the c-axis using THz time-domain, Raman and infrared spectroscopy. Low-freq…
AC and DC Conductivity Anisotropies in Lightly Doped La(2-x)Sr(x)CuO(4)
M. B. Silva Neto, G. Blumberg, A. Gozar +2
The AC and DC conductivity anisotropies in the low temperature orthorhombic phase of lightly doped La(2-x)Sr(x)CuO(4) are ascribed to the rotational symmetry broken, localized impu…
Surface Josephson plasma waves in a high-temperature superconductor
Q. Lu, A. T. Bollinger, X. He +3
Electron density oscillations with acoustic dispersions and sustained at boundaries between different media provide information about surface and interface properties of hetero-str…
Large response of charge stripes to uniaxial stress in
T. J. Boyle, M. Walker, A. Ruiz +17
The La-based '214' cuprates host several symmetry breaking phases including superconductivity, charge and spin order in the form of stripes, and a structural othorhombic-to-tetrago…
Hole crystallization in the spin ladder of Sr14Cu24O41
P. Abbamonte, G. Blumberg, A. Rusydi +7
One of the deepest questions in condensed matter physics concerns what other phases compete with superconductivity in high-transition-temperature (high-Tc) superconductors. One can…
Superconducting transition at 38 K in insulating-overdoped La2CuO4-La1.64Sr0.36CuO4 superlattices: Evidence for interface electronic redistribution from resonant soft x-ray scattering
S. Smadici, J. C. T. Lee, S. Wang +5
We use resonant soft x-ray scattering (RSXS) to quantify the hole distribution in a superlattice of insulating La2CuO4 (LCO) and overdoped La_{2-x}Sr_{x}CuO4 (LSCO). Despite its no…
Insulator to Metal Transition in WO Induced by Electrolyte Gating
X. Leng, J. Pereiro, J. Strle +8
Tungsten oxide and its associated bronzes (compounds of tungsten oxide and an alkali metal) are well known for their interesting optical and electrical characteristics. We have mod…
High-temperature interface superconductivity between metallic and insulating cuprates
A. Gozar, G. Logvenov, L. Fitting Kourkoutis +4
High-temperature superconductivity confined to nanometer-size interfaces has been a long standing goal because of potential applications^{1,2} and the opportunity to study quantum…
Symmetry and light coupling to phononic and collective magnetic excitations in SrCu_2(BO_3)_2
A. Gozar, B. S. Dennis, H. Kageyama +1
We perform a low temperature Raman scattering study of phononic and collective spin excitations in the orthogonal dimers compound SrCu_2(BO_3)_2, focussing on the symmetry and the…
Collective Magnetic Excitations in SrCu_2(BO_3)_2
A. Gozar, G. Blumberg
We study low temperature Raman data on phononic and magnetic excitations in SrCu_2(BO_3)_2. Regarding the former, in the 0 to 350 cm-1 range we find several pairs of quasi-degenera…
Raman scattering through surfaces having biaxial symmetry
A. Gozar
Magnetic Raman scattering in two-leg spin ladder materials and the relationship between the anisotropic exchange integrals are analyzed by P. J. Freitas and R. R. P. Singh in Phys.…
Surface Structure Analysis of Atomically Smooth BaBiO Films
A. Gozar, G. Logvenov, V. Y. Butko +1
Using low energy Time-of-Flight Scattering and Recoil Spectroscopy (TOF-SARS) and Mass Spectroscopy of Recoiled Ions (MSRI) we analyze the surface structure of an atomically smooth…
Superconductivity in La(1.56)Sr(0.44)CuO(4)/La(2)CuO(4) superlattices
A. Suter, E. Morenzoni, T. Prokscha +5
Superlattices of the repeated structure La(1.56)Sr(0.44)CuO(4)/La(2)CuO(4) (LSCO-LCO), where none of the constituents is superconducting, show a superconducting transition of T_c \…
Sliding Density-Wave in Sr_{14}Cu_{24}O_{41} Ladder Compounds
G. Blumberg, P. Littlewood, A. Gozar +4
We used transport and Raman scattering measurements to identify the insulating state of self-doped spin 1/2 two-leg ladders of Sr_{14}Cu_{24}O_{41} as a weakly pinned, sliding dens…