| 1. |
- Chang, Johan, et al.
(författare)
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Anisotropic quasiparticle scattering rates in slightly underdoped to optimally doped high-temperature La2-xSrxCuO4 superconductors
- 2008
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78:20, s. 205103-
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Tidskriftsartikel (refereegranskat)abstract
- An angle-resolved photoemission study of the scattering rate in the superconducting phase of the high-temperature superconductor La2-xSrxCuO4 with x=0.145 and x=0.17, as a function of binding energy and momentum, is presented. We observe that the scattering rate scales linearly with binding energy up to the high-energy scale E-1 similar to 0.4 eV. The scattering rate is found to be strongly anisotropic, with a minimum along the (0,0)-(pi,pi) direction. A possible connection to a quantum-critical point is discussed.
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| 2. |
- Chang, Johan, et al.
(författare)
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When low- and high-energy electronic responses meet in cuprate superconductors
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:22, s. 224508-
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Tidskriftsartikel (refereegranskat)abstract
- The existence of coherent quasiparticles near the Fermi energy in the low-temperature state of high-temperature superconductors has been well established by angle-resolved photoemission spectroscopy (ARPES). We present a study of La1.83Sr0.17CuO4 in the superconducting state and report an abrupt change in the quasiparticle spectral function, as we follow the dispersion of the ARPES signal from the Fermi energy to 0.6 eV. The interruption in the quasiparticle dispersion separates coherent quasiparticle peaks at low energies from broad incoherent excitations at high energies. We find that the boundary between these low-energy and high-energy features exhibits a cosine-shaped momentum dependence, reminiscent of the superconducting d-wave gap. Further intriguing similarities between characteristics of the incoherent excitations and quasiparticle properties suggest a close relation between the electronic response at high and low energies in cuprate superconductors.
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| 3. |
- Claesson, Thomas, et al.
(författare)
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The electronic structure of La(1.48)Nd(0.4)Sr(0.12)CuO(4) probed by high- and low-energy angle-resolved photoelectron spectroscopy : Evolution with probing depth
- 2009
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 80:9, s. 094503-1-094503-6
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Tidskriftsartikel (refereegranskat)abstract
- We present angle-resolved photoelectron spectroscopy data probing the electronic structure of the Nd-substituted high-T-c cuprate La1.48Nd0.4Sr0.12CuO4. Data have been acquired at low and high photon energies, h nu=55 and 500 eV, respectively. The two extracted Fermi surfaces show significant differences. The differences can be attributed to either the change in probing depth suggesting dissimilarity of the intrinsic electronic structure between surface and bulk regions, or a considerable c-axis dispersion signaling a strong interlayer coupling. At both photon energies, considerable spectral weight is observed at all points along the Fermi surface and the intensity distribution as well as Fermi-surface shape observed at low as well as high photon energy is markedly different from what has been previously reported for La1.28Nd0.6Sr0.12CuO4 by Zhou [Science 286, 268 (1999)]. Document Type: Article
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| 4. |
- Graslund, S, et al.
(författare)
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Protein production and purification
- 2008
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Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 5:2, s. 135-146
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Månsson, Martin, et al.
(författare)
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On-board sample cleaver
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:7, s. 076103-
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Tidskriftsartikel (refereegranskat)abstract
- An on-board sample cleaver has been developed in order to cleave small and hard-to-cleave samples. To acquire good cleaves from rigid samples the alignment of the cleaving blade with respect to the internal crystallographic planes is crucial. To have the opportunity to mount the sample and align it to the blade ex situ has many advantages. The design presented has allowed us to cleave very tiny and rigid samples, e.g., the high-temperature superconductor La(2-x)SrxCuO4. Further, in this design the sample and the cleaver will have the same temperature, allowing us to cleave and keep the sample at low temperature. This is a big advantage over prior cleaver systems. As a result, better surfaces and alignments can be realized, which considerably simplifies and improves the experiments.
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| 7. |
- Shi, Ming, et al.
(författare)
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Coherent d-wave superconducting gap in underdoped La2-xSrxCuO4 by angle-resolved photoemission spectroscopy
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:4, s. 047002-
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Tidskriftsartikel (refereegranskat)abstract
- We present angle-resolved photoemission spectroscopy data on moderately underdoped La1.855Sr0.145CuO4 at temperatures below and above the superconducting transition temperature. Unlike previous studies of this material, we observe sharp spectral peaks along the entire underlying Fermi surface in the superconducting state. These peaks trace out an energy gap that follows a simple d-wave form, with a maximum superconducting gap of 14 meV. Our results are consistent with a single gap picture for the cuprates. Furthermore our data on the even more underdoped sample La1.895Sr0.105CuO4 also show sharp spectral peaks, even at the antinode, with a maximum superconducting gap of 26 meV.
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