Emergence of quantum Griffiths singularity in disordered TiN thin films

Fuente: arXiv
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Main Authors: Yadav, Sachin, Saravanan, M. P., Sahoo, Sangeeta
Format: Preprint
Published: 2024
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author Yadav, Sachin
Saravanan, M. P.
Sahoo, Sangeeta
author_facet Yadav, Sachin
Saravanan, M. P.
Sahoo, Sangeeta
contents The association of quantum Griffiths singularity (QGS) to the magnetic-field-induced superconductor-metal transition predicts the unconventional diverging behaviour of dynamical critical exponent in low disorder crystalline two-dimensional superconductors. But whether this state exists in the superconducting systems exhibiting superconductor-insulator transition remains elusive. Here, we report the emergence of quantum Griffiths singularity in ultrathin disordered TiN thin films with more than two orders of magnitude variation in their normal state resistance. For both superconductor-metal transition and superconductor-insulator transition types, a diverging critical exponent is observed while approaching the quantum phase transition. Further, the magnetoresistance isotherms obey a direct activated scaling governed by an infinite-randomness fixed critical point. Finally, this work establishes the robustness of the QGS phenomenon towards a wide range of temperature and also towards a wide range of disorder strength as correlated with the normal state resistance.
format Preprint
id arxiv_https___arxiv_org_abs_2406_16492
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Emergence of quantum Griffiths singularity in disordered TiN thin films
Yadav, Sachin
Saravanan, M. P.
Sahoo, Sangeeta
Superconductivity
The association of quantum Griffiths singularity (QGS) to the magnetic-field-induced superconductor-metal transition predicts the unconventional diverging behaviour of dynamical critical exponent in low disorder crystalline two-dimensional superconductors. But whether this state exists in the superconducting systems exhibiting superconductor-insulator transition remains elusive. Here, we report the emergence of quantum Griffiths singularity in ultrathin disordered TiN thin films with more than two orders of magnitude variation in their normal state resistance. For both superconductor-metal transition and superconductor-insulator transition types, a diverging critical exponent is observed while approaching the quantum phase transition. Further, the magnetoresistance isotherms obey a direct activated scaling governed by an infinite-randomness fixed critical point. Finally, this work establishes the robustness of the QGS phenomenon towards a wide range of temperature and also towards a wide range of disorder strength as correlated with the normal state resistance.
title Emergence of quantum Griffiths singularity in disordered TiN thin films
topic Superconductivity
url https://arxiv.org/abs/2406.16492