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Autori principali: Nakamura, Takuto, Sugihara, Hiroki, Chen, Yitong, Yukawa, Ryu, Ohtsubo, Yoshiyuki, Tanaka, Kiyohisa, Kitamura, Miho, Kumigashira, Hiroshi, Kimura, Shin-ichi
Natura: Preprint
Pubblicazione: 2023
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Accesso online:https://arxiv.org/abs/2306.06984
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author Nakamura, Takuto
Sugihara, Hiroki
Chen, Yitong
Yukawa, Ryu
Ohtsubo, Yoshiyuki
Tanaka, Kiyohisa
Kitamura, Miho
Kumigashira, Hiroshi
Kimura, Shin-ichi
author_facet Nakamura, Takuto
Sugihara, Hiroki
Chen, Yitong
Yukawa, Ryu
Ohtsubo, Yoshiyuki
Tanaka, Kiyohisa
Kitamura, Miho
Kumigashira, Hiroshi
Kimura, Shin-ichi
contents The Kondo effect between localized $f$-electrons and conductive carriers leads to exotic physical phenomena. Among them, heavy-fermion (HF) systems, in which massive effective carriers appear due to the Kondo effect, have fascinated many researchers. Dimensionality is also an important characteristic of the HF system, especially because it is strongly related to quantum criticality [S. Sachdev, Science 288, 475 (2000)]. However, perfect two-dimensional (2D) HF materials have not been reported yet. Here, we report the surface electronic structure of the monoatomic-layer Kondo lattice YbCu$_2$ on a Cu(111) surface observed by synchrotron-based angle-resolved photoelectron spectroscopy. The 2D conducting band and the Yb 4$f$ state, located very close to the Fermi level, are observed. These bands are hybridized at low-temperature, forming the 2D HF state, with an evaluated coherent temperature of about 30 K. The effective mass of the 2D state is enhanced by a factor of 100 by the development of the HF state. Furthermore, clear evidence of the hybridization gap formation in the temperature dependence of the Kondo-resonance peak has been observed below the coherent temperature. Our study provides a new candidate as an ideal 2D HF material for understanding the Kondo effect at low dimensions.
format Preprint
id arxiv_https___arxiv_org_abs_2306_06984
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Two-dimensional heavy fermion in a monoatomic-layer Kondo lattice YbCu$_2$
Nakamura, Takuto
Sugihara, Hiroki
Chen, Yitong
Yukawa, Ryu
Ohtsubo, Yoshiyuki
Tanaka, Kiyohisa
Kitamura, Miho
Kumigashira, Hiroshi
Kimura, Shin-ichi
Strongly Correlated Electrons
Materials Science
The Kondo effect between localized $f$-electrons and conductive carriers leads to exotic physical phenomena. Among them, heavy-fermion (HF) systems, in which massive effective carriers appear due to the Kondo effect, have fascinated many researchers. Dimensionality is also an important characteristic of the HF system, especially because it is strongly related to quantum criticality [S. Sachdev, Science 288, 475 (2000)]. However, perfect two-dimensional (2D) HF materials have not been reported yet. Here, we report the surface electronic structure of the monoatomic-layer Kondo lattice YbCu$_2$ on a Cu(111) surface observed by synchrotron-based angle-resolved photoelectron spectroscopy. The 2D conducting band and the Yb 4$f$ state, located very close to the Fermi level, are observed. These bands are hybridized at low-temperature, forming the 2D HF state, with an evaluated coherent temperature of about 30 K. The effective mass of the 2D state is enhanced by a factor of 100 by the development of the HF state. Furthermore, clear evidence of the hybridization gap formation in the temperature dependence of the Kondo-resonance peak has been observed below the coherent temperature. Our study provides a new candidate as an ideal 2D HF material for understanding the Kondo effect at low dimensions.
title Two-dimensional heavy fermion in a monoatomic-layer Kondo lattice YbCu$_2$
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2306.06984