Low temperature thermodynamics of Seff=1/2 triangular lattice quantum spin liquid candidate TlYbS2
Abstract
Geometrically frustrated triangular-lattice antiferromagnets exhibit a delicate competition between magnetic order and quantum spin liquid (QSL) behavior, with the Yb-based delafossite family AYbX2 providing a structurally clean platform for exploring this physics. Here, we report a comprehensive study of single-crystal TlYbS2 using DC magnetization, AC susceptibility, electron spin resonance (ESR), and specific heat measurements extending from room temperature to the millikelvin regime. Single-crystal X-ray diffraction confirms a trigonal R3̅m structure comprising well-separated triangular layers of Yb3+ ions with no detectable site disorder. At zero field, a weak thermodynamic anomaly is observed near $530$ mK, which may indicate the onset of a weakly ordered state similar to that reported in KYbSe2. Below $300$ mK, the zero-field magnetic specific heat follows Cm∝ T1.8, close to a quadratic temperature dependence, in contrast to the linear temperature dependence reported for the sister compound TlYbSe2, which has been described in terms of the interplay between spinons and thermally excited gauge-flux excitations. Magnetization and ESR measurements establish pronounced easy-plane magnetic anisotropy, with g⊥/g∥ ≈ 6.9. The anomaly near $530$ mK exhibits a strongly anisotropic response to magnetic field. For H⊥ c, it remains visible up to approximately $2$ T and continuously evolves toward a field-induced ordered phase above approximately $2.5$ T, followed by a sequence of field-induced phases that includes a 1/3 magnetization plateau between approximately $5$ and $8$ T and full polarization near $17$ T. In contrast, for H∥ c, the anomaly weakens and is suppressed near $3$ T, consistent with the recently reported confinement--deconfinement transition from an ordered state to a field-induced QSL.
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BibTeX
@misc{belbase2026temperature,
title = {{Low temperature thermodynamics of $S_\mathrmeff=1/2$ triangular lattice quantum spin liquid candidate TlYbS$_2$}},
author = {Bishnu P. Belbase and Arjun Unnikrishnan and Piyush Chhallare and Mohan B. Neupane and Eun Sang Choi and Sebastian Erdmann and Muhammad U. Akbar and Mamoun Hemmida and H. -A. Krug von Nidda and Philipp Gegenwart and Arnab Banerjee},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.11881},
eprint = {2609.11881},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.11881},
}
RIS
TY - UNPB
TI - Low temperature thermodynamics of S_eff=1/2 triangular lattice quantum spin liquid candidate TlYbS_2
AU - Bishnu P. Belbase
AU - Arjun Unnikrishnan
AU - Piyush Chhallare
AU - Mohan B. Neupane
AU - Eun Sang Choi
AU - Sebastian Erdmann
AU - Muhammad U. Akbar
AU - Mamoun Hemmida
AU - H. -A. Krug von Nidda
AU - Philipp Gegenwart
AU - Arnab Banerjee
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2609.11881
UR - https://arxiv.org/abs/2609.11881
AB - Geometrically frustrated triangular-lattice antiferromagnets exhibit a delicate competition between magnetic order and quantum spin liquid (QSL) behavior, with the Yb-based delafossite family AYbX_2 providing a structurally clean platform for exploring this physics. Here, we report a comprehensive study of single-crystal TlYbS_2 using DC magnetization, AC susceptibility, electron spin resonance (ESR), and specific heat measurements extending from room temperature to the millikelvin regime. Single-crystal X-ray diffraction confirms a trigonal R3̅m structure comprising well-separated triangular layers of Yb^3+ ions with no detectable site disorder. At zero field, a weak thermodynamic anomaly is observed near $530$ mK, which may indicate the onset of a weakly ordered state similar to that reported in KYbSe_2. Below $300$ mK, the zero-field magnetic specific heat follows C_m∝ T^1.8, close to a quadratic temperature dependence, in contrast to the linear temperature dependence reported for the sister compound TlYbSe_2, which has been described in terms of the interplay between spinons and thermally excited gauge-flux excitations. Magnetization and ESR measurements establish pronounced easy-plane magnetic anisotropy, with g_⊥/g_∥ ≈ 6.9. The anomaly near $530$ mK exhibits a strongly anisotropic response to magnetic field. For H⊥ c, it remains visible up to approximately $2$ T and continuously evolves toward a field-induced ordered phase above approximately $2.5$ T, followed by a sequence of field-induced phases that includes a 1/3 magnetization plateau between approximately $5$ and $8$ T and full polarization near $17$ T. In contrast, for H∥ c, the anomaly weakens and is suppressed near $3$ T, consistent with the recently reported confinement--deconfinement transition from an ordered state to a field-induced QSL.
ER -