0000000000543044
AUTHOR
Philipp Gegenwart
showing 3 related works from this author
Strain induced renormalization of transport properties in UPt3 thin films
1996
The growth of sputter deposited UPt3 thin films on Al2O3 (1012), LaAlO3 (111) and SrTiO3 (111) was investigated. We found strongly 0001-textured growth of UPt3 in a small compositional range of 23–25% uranium content. For Al2O3-and LaAlO3-substrates no in-plane order could be observed whereas epitaxial growth was initiated on SrTiO3 (111): The growth can be identified as Vollmer-Weber like resulting in the formation of large lateral strain as a consequence of the growth mode and a lattice misfit of −4.3% between UPt3 (0001) and SrTiO3 (111). Strong deviations from the typical heavy-fermion characteristics in electronic transport properties like resistivity, magnetoresitivity and Hall-effect…
Growth characteristics of sputter-deposited thin films
1996
Thin films of the heavy-fermion superconductor were deposited on various substrate materials in various orientations by means of a quasi-multilayer sputter process. Strongly (0001)-textured growth of the hexagonal compound was found for a uranium content in the range of 23% to 28% on sapphire and with perfect in-plane order on the latter substrate material. Atomic force microscopy and scanning electron microscopy revealed a Vollmer - Weber-like growth mode resulting in the development of large compressive strain in films on . As a result the electronic transport properties - in particular the temperature dependence of the resistivity - were strongly renormalized. Strong deviations from the …
Tracking local magnetic dynamics via high-energy charge excitations in a relativistic Mott insulator
2016
We use time- and energy-resolved optical spectroscopy to investigate the coupling of electron-hole excitations to the magnetic environment in the relativistic Mott insulator Na$_2$IrO$_3$. We show that, on the picosecond timescale, the photoinjected electron-hole pairs delocalize on the hexagons of the Ir lattice via the formation of quasi-molecular orbital (QMO) excitations and the exchange of energy with the short-range-ordered zig-zag magnetic background. The possibility of mapping the magnetic dynamics, which is characterized by typical frequencies in the THz range, onto high-energy (1-2 eV) charge excitations provides a new platform to investigate, and possibly control, the dynamics of…