Quantum Spin Ladders in a Magnetic Field: Luttinger liquid, Dimensional crossover and Criticality

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• Dr. Minki Jeong, EPFL
• Monday 06 March 2017, 14:00-15:00
• Physics East 217.

If you have a question about this talk, please contact Elizabeth Blackburn.

Quantum spin ladders in a magnetic field is a paradigmatic model in many-body physics: they display a plethora of exciting behaviour which can often be understood not only qualitatively but also quantitatively. For instance, the ground state of a single Heisenberg spin-1/2 ladder is a gapped spin liquid, but applying a sufficiently strong magnetic field closes the gap and induces a transition into a Tomonaga-Luttinger liquid. In real materials, residual couplings between the ladders become effective at sufficiently low temperature, thereby the Luttinger liquid undergoing a transition into a magnetic Bose-Einstein condensate. Here I briefly overview this field of research, followed by my own contributions. I present NMR experimental evidences that strong leg and strong rung ladders realise respectively attractive and repulsive fermionic interactions in their corresponding Luttinger liquid state [1, 2]. Furthermore, I show a possible experimental evidence of a quasi-two-dimensional order when the couplings between the ladders are highly spatially anisotropic [3], as suggested by a recent theory. If time permits, I discuss aspects of quantum criticality in quasi-low-dimensional quantum magnets [4].

[1] M. Jeong et al., Phys. Rev. Lett. 111, 106404 (2013). [2] M. Jeong et al., Phys. Rev. Lett. 117, 106402 (2016). [3] M. Jeong et al., arXiv:1702.05273. [4] M. Jeong and H. M. Ronnow, Phys. Rev. B 180409 (R) (2015).

This talk is part of the Condensed Matter Physics Seminars series.

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• Bham Talks
• Cond. Mat. seminar
• Condensed Matter Physics Seminars
• Physics East 217
• What's on in Physics?

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