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arXiv · 0902.1191

Field-induced soft-mode quantum phase transition in La$_{1.855}$Sr$_{0.145}$CuO$_{4}$

J. Chang·N. B. Christensen·Ch. Niedermayer·K. Lefmann·H. M. Roennow·D. F. McMorrow·A. Schneidewind·P. Link·A. Hiess·M. Boehm·R. Mottl·S. Pailhes·N. Momono·M. Oda·M. Ido·J. Mesot
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Abstract

Inelastic neutron-scattering experiments on the high-temperature superconductor La$_{1.855}$Sr$_{0.145}$CuO$_{4}$ reveal a magnetic excitation gap $Δ$ that decreases continuously upon application of a magnetic field perpendicular to the CuO$_2$ planes. The gap vanishes at the critical field required to induce long-range incommensurate antiferromagnetic order, providing compelling evidence for a field-induced soft-mode driven quantum phase transition.

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J. Chang, N. B. Christensen, Ch. Niedermayer, K. Lefmann, H. M. Roennow, D. F. McMorrow, A. Schneidewind, P. Link, A. Hiess, M. Boehm, R. Mottl, S. Pailhes, N. Momono, M. Oda, M. Ido, J. Mesot. 2009-02-06. Field-induced soft-mode quantum phase transition in La$_{1.855}$Sr$_{0.145}$CuO$_{4}$. https://doi.org/10.1103/physrevlett.102.177006

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