The square-kagome quantum Heisenberg antiferromagnet at high magnetic fields: the localized-magnon paradigm and beyond

• Veröffentlicht in: Физика низких температур
• Datum: 2014
• Hauptverfasser: Derzhko, O., Richter, J., Krupnitska, O., Krokhmalskii, T.
• Format: Artikel
• Sprache: English
• Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2014
• Schlagworte: Низкотемпеpатуpный магнетизм
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/119527
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: The square-kagome quantum Heisenberg antiferromagnet at high magnetic fields: the localized-magnon paradigm and beyond / O. Derzhko, J. Richter, O. Krupnitska, T. Krokhmalskii // Физика низких температур. — 2014. — Т. 40, № 6. — С. 662-670. — Бібліогр.: 43 назв. — англ.

We consider the spin-1/2 antiferromagnetic Heisenberg model on the two-dimensional square-kagome lattice with almost dispersionless lowest magnon band. For a general exchange coupling geometry we elaborate low-energy effective Hamiltonians which emerge at high magnetic fields. The effective model to describe the low-energy degrees of freedom of the initial frustrated quantum spin model is the (unfrustrated) square-lattice spin-1/2 XXZ model in a z-aligned magnetic field. For the effective model we perform quantum Monte Carlo simulations to discuss the low-temperature properties of the square-kagome quantum Heisenberg antiferromagnet at high magnetic fields. We pay special attention to a magnetic-field driven Berezinskii–Kosterlitz– Thouless phase transition which occurs at low temperatures.