Naslov
Quantum criticality of α-YbAlB4

Autori
Grbić, Mihael Srđan ; Kimura, Kazuhiro ; Yoshida, Makoto ; Takigawa, Masashi ; Kuga, Kentaro ; Nakatsuji, Satoru

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Abstract Booklet of SCES 2013 Tokyo / - Tokyo, 2013

Skup
International Conference on Strongly Correlated Electron Systems

Mjesto i datum
Tokyo, Japan, 05.08.2013. - 09.08.2013

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
criticality; heavy fermion; nmr

Sažetak
α-YbAlB4 is a structural isomorph of the heavy fermion compound β-YbAlB4, in which quantum criticality [1, 2] marked by non-Fermi-liquid properties and low-temperature superconductivity [2], has recently been discovered at zero magnetic field. Although both compounds show similar fluctuating valence value of Yb2+/Yb3+ ions, α-YbAlB4 shows Fermi-liquid properties with no signs of quantum critical behaviour. Such large variation of ground states has been ascribed to the difference in the local symmetry of boron rings around Yb which modify the energy spectrum of the system. We look for signatures of magnetic field-induced quantum criticality by nuclear magnetic resonance. At low temperatures, the spin-lattice relaxation rate (1/T1) shows a clear departure from the Fermi-liquid behaviour. This increase of spin excitations is sensitive to magnetic field and close to 3.5 T shows divergent temperature dependence down to 50 mK, indicating the vicinity of a quantum critical point. We discuss the properties of the new emerging phase and compare it to existing models on heavy fermion systems. [1] S. Nakatsuji et al., Nature Phys. 4, 603 (2008). [2] Y. Matsumoto, S. Nakatsuji et al., Science 331, 316 (2011).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA