Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/101789
Title: Thermodynamic evidence of fractionalized excitations in α-RuC l3
Authors: Widmann, S.
Tsurkan, V.
Prishchenko, D. A.
Mazurenko, V. G.
Tsirlin, A. A.
Loidl, A.
Issue Date: 2019
Publisher: American Physical Society
Citation: Thermodynamic evidence of fractionalized excitations in α-RuC l3 / S. Widmann, V. Tsurkan, D. A. Prishchenko, et al. — DOI 10.1103/PhysRevB.99.094415 // Physical Review B. — 2019. — Vol. 99. — Iss. 9. — 094415.
Abstract: Fractionalized excitations are of considerable interest in recent condensed-matter physics. Fractionalization of the spin degrees of freedom into localized and itinerant Majorana fermions is predicted for the Kitaev spin liquid, an exactly solvable model with bond-dependent interactions on a two-dimensional honeycomb lattice. As a function of temperature, theory predicts a characteristic two-peak structure of the heat capacity as a fingerprint of these excitations. Here we report on detailed heat-capacity experiments as a function of temperature and magnetic field in high-quality single crystals of α-RuCl3. We undertook considerable efforts to determine the exact phonon background. We measured single-crystalline RhCl3 as a nonmagnetic reference and performed ab initio calculations of the phonon density of states for both compounds. These ab initio calculations document that the intrinsic phonon contribution to the heat capacity cannot be obtained by a simple rescaling of the nonmagnetic reference using differences in the atomic masses. Sizable renormalization is required even for nonmagnetic RhCl3 with its minute difference from the title compound. In α-RuCl3 in zero magnetic field, excess heat capacity exists at temperatures well above the onset of magnetic order. In external magnetic fields far beyond quantum criticality, when long-range magnetic order is fully suppressed, the excess heat capacity exhibits the characteristic two-peak structure. In zero field, the lower peak just appears at temperatures around the onset of magnetic order and seems to be connected with canonical spin degrees of freedom. At higher fields, beyond the critical field, this peak is shifted to 10 K. The high-temperature peak located around 70 K is hardly influenced by external magnetic fields, carries the predicted amount of entropy R/2ln2, and may resemble remnants of Kitaev physics. © 2019 American Physical Society.
Keywords: CALCULATIONS
CHLORINE COMPOUNDS
DEGREES OF FREEDOM (MECHANICS)
HIGH ENERGY PHYSICS
HONEYCOMB STRUCTURES
ISOMERS
MAGNETIC FIELDS
PHONONS
RHODIUM COMPOUNDS
SILICON COMPOUNDS
SINGLE CRYSTALS
TEMPERATURE
AB INITIO CALCULATIONS
EXACTLY SOLVABLE MODEL
EXTERNAL MAGNETIC FIELD
HIGH QUALITY SINGLE CRYSTALS
HIGH TEMPERATURE PEAKS
LONG RANGE MAGNETIC ORDER
PHONON DENSITY OF STATE
SPIN DEGREES OF FREEDOM
SPECIFIC HEAT
URI: http://hdl.handle.net/10995/101789
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85063150707
PURE ID: 9178419
d9697154-1ea8-424f-a612-be1cbe42cd36
ISSN: 24699950
DOI: 10.1103/PhysRevB.99.094415
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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