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arXiv · 1608.01840

Direct bulk sensitive probe of 5f symmetry in URu2Si2

Martin Sundermann·Maurits W. Haverkort·Stefano Agrestini·Ali Al-Zein·Marco Moretti Sala·Yingkai Huang·Mark Golden·Anne de Visser·Peter Thalmeier·Liu Hao Tjeng·Andrea Severing
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Abstract

The second-order phase transition into a hidden order phase in URu$_2$Si$_2$ goes along with an order parameter which is still a mystery, despite 30 years of research. However, it is understood that the symmetry of the order parameter must be related to the symmetry of the low lying local electronic $f$-states. Here we present results of a novel spectroscopy, namely core-level non-resonant inelastic x-ray scattering (NIXS). This method allows for the measurement of local high-multipole excitations and it is bulk sensitive. The observed anisotropy of the scattering function unambiguously shows that the 5$f$ ground state wave function is composed mainly, but essentially not purely, of the $\Gamma_1$ with majority $J_z$ =$|4\rangle$ + $|-4\rangle$ and/or $\Gamma_2$ singlet states.

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Martin Sundermann, Maurits W. Haverkort, Stefano Agrestini, Ali Al-Zein, Marco Moretti Sala, Yingkai Huang, Mark Golden, Anne de Visser, Peter Thalmeier, Liu Hao Tjeng, Andrea Severing. 2016-08-05. Direct bulk sensitive probe of 5f symmetry in URu2Si2. https://doi.org/10.1073/pnas.1612791113

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