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arXiv · 2609.30518

Nuclear spin-lattice relaxation rate near a two-dimensional antiferromagnetic quantum critical point

Yutaka Itoh
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Abstract

We study the effects of zero-point spin fluctuations on the nuclear spin-lattice relaxation rate 1/$T_1$ around a two-dimensional antiferromagnetic quantum critical point in the self-consistent renormalization theory. For a weak mode-mode coupling constant $y_1 < $ 0.1, the finite temperature behavior of 1/$T_1$ across the quantum critical point resembles that for only the thermal spin fluctuations. For a strong mode-mode coupling constant $y_1 > $ 0.1, 1/$T_1$ takes its local maximum as a function of temperature in the nearly antiferromagnetic state. Experimental observation of the local maximum in the $^{63}$Cu nuclear spin-lattice relaxation rate 1/$T_1$ of lightly-doped superconductors La$_{2-x}$Sr$_x$CuO$_4$ with $x$ = 0.06-0.10 is associated with the effects of the zero-point spin fluctuations. The two-dimensional magnetic quantum critical point and the role of the zero-point spin fluctuations are discussed in the electron spin dynamics of underdoped superconductors La$_{2-x}$Sr$_x$CuO$_4$.

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Yutaka Itoh. 2026-09-24. Nuclear spin-lattice relaxation rate near a two-dimensional antiferromagnetic quantum critical point. https://arxiv.org/abs/2609.30518

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