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Quantum phase transitions of magnetic rotons

Joerg Schmalian·Misha Turlakov·;
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Abstract

Due to weak spin-orbit coupling, the magnetic excitations of an itinerant ferromagnet become magnetic rotons, excitations with degenerate minima on a hypersphere at finite wavevector. Using self-consistent Hartree and renormalization group calculations, we study weak fluctuation-driven first-order quantum phase transitions, a quantum tricritical point controlled by anisotropy and the non-Fermi liquid behavior associated with the large phase volume of magnetic rotons. We propose that magnetic rotons are essential for the description of the anomalous high-pressure behavior of the itinerant helical ferromagnet MnSi.

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Joerg Schmalian, Misha Turlakov, ;. 2004-02-17. Quantum phase transitions of magnetic rotons. https://doi.org/10.1103/physrevlett.93.036405

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