Majorana fermions in the Kitaev quantum spin system α-RuCl3

被引:357
作者
Do, Seung-Hwan [1 ,2 ]
Park, Sang-Youn [2 ]
Yoshitake, Junki [3 ]
Nasu, Joji [4 ]
Motome, Yukitoshi [3 ]
Kwon, Yong Seung [5 ]
Adroja, D. T. [6 ,7 ]
Voneshen, D. J. [6 ]
Kim, Kyoo [2 ]
Jang, T. -H. [2 ]
Park, J. -H. [2 ,8 ,9 ]
Choi, Kwang-Yong [1 ]
Ji, Sungdae [2 ,8 ]
机构
[1] Chung Ang Univ, Dept Phys, Seoul 06974, South Korea
[2] POSTECH, Hsinchu Ctr Complex Phase Mat, Max Planck POSTECH, Pohang 37673, South Korea
[3] Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan
[4] Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan
[5] DGIST, Dept Emerging Mat Sci, Daegu 42988, South Korea
[6] Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England
[7] Univ Johannesburg, Phys Dept, Highly Correlated Matter Res Grp, POB 524, ZA-2006 Auckland Pk, South Africa
[8] POSTECH, Dept Phys, Pohang 37673, South Korea
[9] POSTECH, Div Adv Mat Sci, Pohang 37673, South Korea
基金
新加坡国家研究基金会;
关键词
STATE; ANYONS;
D O I
10.1038/nphys4264
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Geometrical constraints to the electronic degrees of freedom within condensed-matter systems often give rise to topological quantum states of matter such as fractional quantum Hall states, topological insulators, and Weyl semimetals(1-3). In magnetism, theoretical studies predict an entangled magnetic quantum state with topological ordering and fractionalized spin excitations, the quantum spin liquid(4). In particular, the so-called Kitaev spin model(5), consisting of a network of spins on a honeycomb lattice, is predicted to host Majorana fermions as its excitations. By means of a combination of specific heat measurements and inelastic neutron scattering experiments, we demonstrate the emergence of Majorana fermions in single crystals of alpha-RuCl3, an experimental realization of the Kitaev spin lattice. The specific heat data unveils a two-stage release of magnetic entropy that is characteristic of localized and itinerant Majorana fermions. The neutron scattering results corroborate this picture by revealing quasielastic excitations at low energies around the Brillouin zone centre and an hour-glass-like magnetic continuum at high energies. Our results confirm the presence of Majorana fermions in the Kitaev quantum spin liquid and provide an opportunity to build a unified conceptual framework for investigating fractionalized excitations in condensed matter(1,6-8).
引用
收藏
页码:1079 / +
页数:7
相关论文
共 32 条
[1]   THE RESONATING VALENCE BOND STATE IN LA2CUO4 AND SUPERCONDUCTIVITY [J].
ANDERSON, PW .
SCIENCE, 1987, 235 (4793) :1196-1198
[2]   Spin liquids in frustrated magnets [J].
Balents, Leon .
NATURE, 2010, 464 (7286) :199-208
[3]  
Banerjee A, 2016, NAT MATER, V15, P733, DOI [10.1038/nmat4604, 10.1038/NMAT4604]
[4]   Neutron scattering in the proximate quantum spin liquid α-RuCl3 [J].
Banerjee, Arnab ;
Yan, Jiaqiang ;
Knolle, Johannes ;
Bridges, Craig A. ;
Stone, Matthew B. ;
Lumsden, Mark D. ;
Mandrus, David G. ;
Tennant, David A. ;
Moessner, Roderich ;
Nagler, Stephen E. .
SCIENCE, 2017, 356 (6342) :1055-1058
[5]   Exact results for spin dynamics and fractionalization in the Kitaev model [J].
Baskaran, G. ;
Mandal, Saptarshi ;
Shankar, R. .
PHYSICAL REVIEW LETTERS, 2007, 98 (24)
[6]   Low-temperature crystal and magnetic structure of α-RuCl3 [J].
Cao, H. B. ;
Banerjee, A. ;
Yan, J. -Q. ;
Bridges, C. A. ;
Lumsden, M. D. ;
Mandrus, D. G. ;
Tennant, D. A. ;
Chakoumakos, B. C. ;
Nagler, S. E. .
PHYSICAL REVIEW B, 2016, 93 (13)
[7]  
Catuneanu A., 2017, PREPRINT
[8]   Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na2IrO3 [J].
Choi, S. K. ;
Coldea, R. ;
Kolmogorov, A. N. ;
Lancaster, T. ;
Mazin, I. I. ;
Blundell, S. J. ;
Radaelli, P. G. ;
Singh, Yogesh ;
Gegenwart, P. ;
Choi, K. R. ;
Cheong, S. -W. ;
Baker, P. J. ;
Stock, C. ;
Taylor, J. .
PHYSICAL REVIEW LETTERS, 2012, 108 (12)
[9]   Colloquium: Majorana fermions in nuclear, particle, and solid-state physics [J].
Elliott, Steven R. ;
Franz, Marcel .
REVIEWS OF MODERN PHYSICS, 2015, 87 (01)
[10]   HORACE: Software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments [J].
Ewings, R. A. ;
Buts, A. ;
Le, M. D. ;
van Duijn, J. ;
Bustinduy, I. ;
Perring, T. G. .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2016, 834 :132-142