Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 50: Correlated Electrons: Frustrated Magnets - Theory
TT 50.4: Vortrag
Mittwoch, 9. März 2016, 15:45–16:00, H18
Quantum disordered insulating phase in the frustrated cubic-lattice Hubbard model — •Stephan Rachel1, Manuel Laubach1,2, Darshan Joshi1, Johannes Reuther3, Ronny Thomale2, and Matthias Vojta1 — 1TU Dresden, Institut für Theoretische Physik — 2Universität Würzburg, Institut für Theoretische Physik — 3FU Berlin & Helmholtz-Zentrum Berlin
In the quest for quantum spin liquids in three spatial dimensions (3D), we study the half-filled Hubbard model on the simple cubic lattice with hopping processes up to third neighbors. Employing the variational cluster approach (VCA), we determine the zero-temperature phase diagram: In addition to a paramagnetic metal at small interaction strength U and various antiferromagnetic insulators at large U, we find an intermediate-U antiferromagnetic metal. Most interestingly, we also identify a non-magnetic insulating region, extending from intermediate to strong U. Using VCA results in the large-U limit, we establish the phase diagram of the corresponding J1–J2–J3 Heisenberg model. This is qualitatively confirmed – including the non-magnetic region – using spin-wave theory. Further analysis reveals a striking similarity to the behavior of the J1–J2 square-lattice Heisenberg model, suggesting that the non-magnetic region hosts a 3D spin-liquid phase.