Spin excitations in a single La2CuO4 layer
Research output: Contribution to journal › Research article › Contributed › peer-review
Contributors
Abstract
Cuprates and other high-temperature superconductors consist of two-dimensional layers that are crucial to their properties. The dynamics of the quantum spins in these layers lie at the heart of the mystery of the cuprates. In bulk cuprates such as La2CuO4, the presence of a weak coupling between the two-dimensional layers stabilizes a three-dimensional magnetic order up to high temperatures. In a truly two-dimensional system however, thermal spin fluctuations melt long-range order at any finite temperature. Here, we measure the spin response of isolated layers of La 2CuO4 that are only one-unit-cell-thick. We show that coherent magnetic excitations, magnons, known from the bulk order, persist even in a single layer of La2CuO4, with no evidence for more complex correlations such as resonating valence bond correlations. These magnons are, therefore, well described by spin-wave theory (SWT). On the other hand, we also observe a high-energy magnetic continuum in the isotropic magnetic response that is not well described by two-magnon SWT, or indeed any existing theories.
Details
Original language | English |
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Pages (from-to) | 850-854 |
Number of pages | 5 |
Journal | Nature materials |
Volume | 11 |
Issue number | 10 |
Publication status | Published - Oct 2012 |
Peer-reviewed | Yes |
Externally published | Yes |