Dimension-Dependent Critical Scaling Analysis and Emergent Competing Interaction Scales in a 2D Van der Waals magnet Cr$_{2}$Ge$_{2}$Te$_{6}$

Fuente: arXiv
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Autori principali: Mahato, P. C., Saha, Suprotim, Das, Bikash, Datta, Subhadeep, Mondal, Rajib, Mal, Sourav, Garg, Ashish, Sen, Prasenjit, Banerjee, S. S.
Natura: Preprint
Pubblicazione: 2024
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author Mahato, P. C.
Saha, Suprotim
Das, Bikash
Datta, Subhadeep
Mondal, Rajib
Mal, Sourav
Garg, Ashish
Sen, Prasenjit
Banerjee, S. S.
author_facet Mahato, P. C.
Saha, Suprotim
Das, Bikash
Datta, Subhadeep
Mondal, Rajib
Mal, Sourav
Garg, Ashish
Sen, Prasenjit
Banerjee, S. S.
contents We investigate thickness-dependent transformation from a paramagnetic to ferromagnetic phase in Cr$_{2}$Ge$_{2}$Te$_{6}$ (CGT) in bulk and few-layer flake forms. 2D Ising-like critical transition in bulk CGT occurs at $T_{c}$ = 67 K with out-of-plane magnetic anisotropy. Few-layer CGT on hBN/SiO$_{2}$/Si substrate displays the same $T_{c}$ but also exhibits a new critical transition at $T^{\prime}_c$ = 14.2 K. Here, critical scaling analysis reveals the critical exponents differ significantly from those in bulk and do not align with the known universality classes. Our Density Functional Theory (DFT) and classical calculations indicate competition between magnetocrystalline and dipolar anisotropy emerges with reduced dimensions. The observed behavior is due to minor structural distortions in low dimensional CGT, which modify the balance between spin-orbit coupling, exchange interactions and dipolar anisotropy. This triggers a critical crossover at $T^{\prime}_c$. Our study shows the emergence of a complex interplay of short- and long-range interactions below $T^{\prime}_c$ as CGT approaches the 2D limit.
format Preprint
id arxiv_https___arxiv_org_abs_2402_09741
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dimension-Dependent Critical Scaling Analysis and Emergent Competing Interaction Scales in a 2D Van der Waals magnet Cr$_{2}$Ge$_{2}$Te$_{6}$
Mahato, P. C.
Saha, Suprotim
Das, Bikash
Datta, Subhadeep
Mondal, Rajib
Mal, Sourav
Garg, Ashish
Sen, Prasenjit
Banerjee, S. S.
Materials Science
We investigate thickness-dependent transformation from a paramagnetic to ferromagnetic phase in Cr$_{2}$Ge$_{2}$Te$_{6}$ (CGT) in bulk and few-layer flake forms. 2D Ising-like critical transition in bulk CGT occurs at $T_{c}$ = 67 K with out-of-plane magnetic anisotropy. Few-layer CGT on hBN/SiO$_{2}$/Si substrate displays the same $T_{c}$ but also exhibits a new critical transition at $T^{\prime}_c$ = 14.2 K. Here, critical scaling analysis reveals the critical exponents differ significantly from those in bulk and do not align with the known universality classes. Our Density Functional Theory (DFT) and classical calculations indicate competition between magnetocrystalline and dipolar anisotropy emerges with reduced dimensions. The observed behavior is due to minor structural distortions in low dimensional CGT, which modify the balance between spin-orbit coupling, exchange interactions and dipolar anisotropy. This triggers a critical crossover at $T^{\prime}_c$. Our study shows the emergence of a complex interplay of short- and long-range interactions below $T^{\prime}_c$ as CGT approaches the 2D limit.
title Dimension-Dependent Critical Scaling Analysis and Emergent Competing Interaction Scales in a 2D Van der Waals magnet Cr$_{2}$Ge$_{2}$Te$_{6}$
topic Materials Science
url https://arxiv.org/abs/2402.09741