Quantum Impurity in a Nearly Critical Two Dimensional Antiferromagnet

Fuente: arXiv
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Main Authors: Sachdev, Subir, Buragohain, Chiranjeeb, Vojta, Matthias
Format: Preprint
Published: 2000
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author Sachdev, Subir
Buragohain, Chiranjeeb
Vojta, Matthias
author_facet Sachdev, Subir
Buragohain, Chiranjeeb
Vojta, Matthias
contents We describe the spin dynamics of an arbitrary localized impurity in an insulating two dimensional antiferromagnet, across the host transition from a paramagnet with a spin gap to a Neel state. The impurity spin susceptibility has a Curie-like divergence at the quantum-critical coupling, but with a universal, effective spin which is neither an integer nor a half-odd-integer. In the Neel state, the transverse impurity susceptibility is a universal number divided by the host spin stiffness (which determines the energy cost to slow twists in the orientation of the Neel order). These, and numerous other results for the thermodynamics, Knight shift, and magnon damping have significant applications to experiments on layered transition metal oxides.
format Preprint
id arxiv_https___arxiv_org_abs_cond_mat_0004156
institution arXiv
publishDate 2000
record_format arxiv
spellingShingle Quantum Impurity in a Nearly Critical Two Dimensional Antiferromagnet
Sachdev, Subir
Buragohain, Chiranjeeb
Vojta, Matthias
Strongly Correlated Electrons
Superconductivity
We describe the spin dynamics of an arbitrary localized impurity in an insulating two dimensional antiferromagnet, across the host transition from a paramagnet with a spin gap to a Neel state. The impurity spin susceptibility has a Curie-like divergence at the quantum-critical coupling, but with a universal, effective spin which is neither an integer nor a half-odd-integer. In the Neel state, the transverse impurity susceptibility is a universal number divided by the host spin stiffness (which determines the energy cost to slow twists in the orientation of the Neel order). These, and numerous other results for the thermodynamics, Knight shift, and magnon damping have significant applications to experiments on layered transition metal oxides.
title Quantum Impurity in a Nearly Critical Two Dimensional Antiferromagnet
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/cond-mat/0004156