Quantum half-orphans in kagome antiferromagnets
| Autor: | Patil, Pranay, Alet, Fabien, Capponi, Sylvain, Damle, Kedar |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Phys. Rev. Research 2, 043425 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevResearch.2.043425 |
| Popis: | We numerically study the effects of non-magnetic impurities (vacancies) in the spin-$S$ Heisenberg antiferromagnet on the kagom\'e lattice. For a range of low but nonzero temperatures, and spin values that extend down to $S=2$, we find that the magnetization response to an external magnetic field is consistent with the response of emergent "half-orphan" degrees of freedom that are expected to dominate the response of the corresponding classical magnet in a similar temperature range whenever there are two vacancies on the same triangle. Specifically, for all spin values we have considered (from $S=1/2$ to $S=4$), there is a large enhancement of the local susceptibility of the lone spin on such a triangle with two vacancies; in the presence of a uniform magnetic field $h$, this lone-spin behaves effectively as an almost free spin $S$ in an effective field $h/2$. Quite remarkably, in the zero temperature limit, the ground state in the presence of a half-orphan has a non-zero total spin value $S_{GS}$ that shows a trend similar to $S/2$ when $S\ge 2$. These qualitative aspects of the response differ strikingly from the more conventional response of diluted samples without such half-orphan degrees of freedom. We discuss how these findings could be checked experimentally. Comment: 15 pages, 15 figures |
| Databáze: | arXiv |
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