Quantum fluctuations lead to glassy electron dynamics in the good metal regime of electron doped KTaO3

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Main Authors: Ojha, Shashank Kumar, Hazra, Sankalpa, Bera, Surajit, Gogoi, Sanat Kumar, Mandal, Prithwijit, Maity, Jyotirmay, Gloskovskii, A., Schlueter, C., Karmakar, Smarajit, Jain, Manish, Banerjee, Sumilan, Gopalan, Venkatraman, Middey, Srimanta
Format: Preprint
Published: 2023
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author Ojha, Shashank Kumar
Hazra, Sankalpa
Bera, Surajit
Gogoi, Sanat Kumar
Mandal, Prithwijit
Maity, Jyotirmay
Gloskovskii, A.
Schlueter, C.
Karmakar, Smarajit
Jain, Manish
Banerjee, Sumilan
Gopalan, Venkatraman
Middey, Srimanta
author_facet Ojha, Shashank Kumar
Hazra, Sankalpa
Bera, Surajit
Gogoi, Sanat Kumar
Mandal, Prithwijit
Maity, Jyotirmay
Gloskovskii, A.
Schlueter, C.
Karmakar, Smarajit
Jain, Manish
Banerjee, Sumilan
Gopalan, Venkatraman
Middey, Srimanta
contents One of the central challenges in condensed matter physics is to comprehend systems that have strong disorder and strong interactions. In the strongly localized regime, their subtle competition leads to glassy electron dynamics which ceases to exist well before the insulator-to-metal transition is approached as a function of doping. Here, we report on the discovery of glassy electron dynamics deep inside the good metal regime of an electron-doped quantum paraelectric system: KTaO$_3$. We reveal that upon excitation of electrons from defect states to the conduction band, the excess injected carriers in the conduction band relax in a stretched exponential manner with a large relaxation time, and the system evinces simple aging phenomena - a telltale sign of glassy dynamics. Most significantly, we observe a critical slowing down of carrier dynamics below 35 K, concomitant with the onset of quantum paraelectricity in the undoped KTaO$_3$. Our combined investigation using second harmonic generation technique, density functional theory and phenomenological modeling demonstrates quantum fluctuation-stabilized soft polar modes as the impetus for the glassy behavior. This study addresses one of the most fundamental questions regarding the potential promotion of glassiness by quantum fluctuations and opens a route for exploring glassy dynamics of electrons in a well-delocalized regime.
format Preprint
id arxiv_https___arxiv_org_abs_2306_14464
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Quantum fluctuations lead to glassy electron dynamics in the good metal regime of electron doped KTaO3
Ojha, Shashank Kumar
Hazra, Sankalpa
Bera, Surajit
Gogoi, Sanat Kumar
Mandal, Prithwijit
Maity, Jyotirmay
Gloskovskii, A.
Schlueter, C.
Karmakar, Smarajit
Jain, Manish
Banerjee, Sumilan
Gopalan, Venkatraman
Middey, Srimanta
Strongly Correlated Electrons
Disordered Systems and Neural Networks
One of the central challenges in condensed matter physics is to comprehend systems that have strong disorder and strong interactions. In the strongly localized regime, their subtle competition leads to glassy electron dynamics which ceases to exist well before the insulator-to-metal transition is approached as a function of doping. Here, we report on the discovery of glassy electron dynamics deep inside the good metal regime of an electron-doped quantum paraelectric system: KTaO$_3$. We reveal that upon excitation of electrons from defect states to the conduction band, the excess injected carriers in the conduction band relax in a stretched exponential manner with a large relaxation time, and the system evinces simple aging phenomena - a telltale sign of glassy dynamics. Most significantly, we observe a critical slowing down of carrier dynamics below 35 K, concomitant with the onset of quantum paraelectricity in the undoped KTaO$_3$. Our combined investigation using second harmonic generation technique, density functional theory and phenomenological modeling demonstrates quantum fluctuation-stabilized soft polar modes as the impetus for the glassy behavior. This study addresses one of the most fundamental questions regarding the potential promotion of glassiness by quantum fluctuations and opens a route for exploring glassy dynamics of electrons in a well-delocalized regime.
title Quantum fluctuations lead to glassy electron dynamics in the good metal regime of electron doped KTaO3
topic Strongly Correlated Electrons
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2306.14464