[Zurück]

Sami Dzsaber, L. Prochaska, A. Sidorenko, Gaku Eguchi, R. Svagera, M. Waas, A. Prokofiev, Q. Si, S. Paschen:
"Crossover from Kondo insulator to semimetal by tuning spin-orbit coupling";
Vortrag: 1st German-Austrian Conference on Crystal Growth (GACCG/DKT2018), Wien; 14.02.2018 - 16.02.2018.

The discovery of topologically non-trivial bandstructures in non-interacting
electron systems has triggered an enormous effort to look for their strongly
interacting counterparts. Sofar, bulk insulating phases were at focus in Kondo
systems1 but recently, a bulk metallic phase, the Weyl-Kondo semimetal - that
emerge in correlated electron systems hosted by crystals with broken
inversion symmetry2 - was put forward. Herein, we present the growth of a
series of Ce3Bi4(Pt1-xPdx)3 single crystals3 starting form the archetypal noncentrosymmetric
Kondo insulator Ce3Bi4Pt3 (ref. 4). We show that the
substitution series is iso-structural, iso-electronic and iso-size. This allows to
directly address the spin-orbit coupling (SOC) strength as a tuning parameter,
due to the sizeable mass diference between the Pt and Pd atoms.
Surprisingly, transport and thermodynamic measurements show a crossover
from a Kondo insulator to a strongly correlated semimetal, that we attribute to
the decrease in SOC. Most interestingly, the low-temperature electronic
specific heat coefficient Cel/T of Ce3Bi4Pd3 is linear in T 2. This is the hallmark
of a strongly correlated system with linear electronic dispersion, just as
recently predicted for a Weyl-Kondo semimetal2.
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∗ We gratefully acknowledge financial support from the Austrian Science Fund
(doctoral program W1243 and I2535-N27) and the U.S. Army Research Office (ARO
Grant No.W911NF-14-1-0496) in Vienna, and the ARO (Grant No.W911NF-14-1-
0525) and the Robert A. Welch Foundation (Grant No. C-1411) at Rice.
1 M. Dzero, J. Xia, V. Galitski and P. Coleman, Rev. Condens. Matter. Phys, 7, 249
(2016).
2 H.-H. Lai, S. E. Grefe, S. Paschen, and Q. Si, PNAS, 115, 93 (2018)
3 S. Dzsaber, L. Prochaska, A. Sidorenko, G. Eguchi, R. Svagera, M. Waas, A.
Prokofiev, Q. Si, and S. Paschen, Phys. Rev. Lett., 118, 246601 (2017).
4 M. Jaime, R. Movshovich, G. Stewart, W. Beyermann, M. Berisso, M. Hundley, P.
Canfield, and J. Sarrao, Nature, 45, 160 (2000).

Topology, Kondo, Spin-orbit coupling