Ferromagnetic quantum critical point and strange metal behavior in a clean Kondo lattice

by Prof. Michael Smidman (Zhejiang University)

Wednesday 24 Jan 2024, 10:30 → 11:30 Asia/Shanghai

TDLI Meeting Room N499Prof. Michael Smidman, Zhejiang University

Abstract

Quantum critical points have been found in various antiferromagnetic systems upon the continuous suppression of antiferromagnetic order by non-thermal tuning parameters such as pressure, doping and magnetic fields, giving rise to a rich variety of unusual phenomena such as non-Fermi liquid behavior, unconventional superconductivity, and spin nematicity. In contrast, ferromagnetic quantum critical points are not typically observed experimentally, and were theoretically predicted to be forbidden in clean ferromagnetic systems [1].
We have examined the clean stoichiometric Kondo ferromagnet CeRh6Ge4, where we find that the Curie temperature TC decreases upon applying hydrostatic pressure, and is continuously suppressed to zero at a quantum critical point under a moderate pressure of pc=0.8 GPa [2]. In the vicinity of this ferromagnetic quantum critical point, there is an extended region of strange metal behavior, with a linear-in-temperature resistivity and a logarithmic divergence of the specific heat coefficient, which is remarkably similar to that observed in the optimally doped cuprate superconductors. We have performed a range of further experimental studies in order to reveal the origin and nature of the ferromagnetic quantum criticality, including probing quantum oscillations [3], ARPES [4], as well as neutron scattering and muon spin relaxation/rotation [5]. In particular, I will discuss the effects of chemical doping, whereby the disorder introduced by some dopants destroys the T-linear resistivity [6,7], whereas in other cases the quantum critical point and strange metal behavior is preserved, allowing for additional probes of the ferromagnetic quantum criticality at ambient pressure.
[1] M. Brando, D. Belitz, F. M. Grosche, T. R. Kirkpatrick, Rev. Mod. Phys. 88, 025006 (2016).
[2] B. Shen, Y. J. Zhang, Y. Komijani, M. Nicklas, R. Borth, A. Wang, Y. Chen, Z. Y. Nie, R. Li, X. Lu, H. Lee, M. Smidman, F. Steglich, P. Coleman, H. Q. Yuan, Nature 579, 51-55 (2020).
[3] A. Wang, F. Du, Y. J. Zhang, D. Graf, B. Shen, Y. Chen, Y. Liu, M. Smidman, C. Cao, F. Steglich, H. Q. Yuan, Science Bulletin 66, 1389-1394 (2021).
[4] Y. Wu, Y. J. Zhang, F. Du, B. Shen, H. Zheng, Y. Fang, M. Smidman, C. Cao, F. Steglich, H. Q. Yuan, J. D. Denlinger, and Y. Liu, Phys. Rev. Lett. 126, 216406 (2021).
[5] J. W. Shu, D. T. Adroja, A. D. Hillier, Y. J. Zhang, Y. X. Chen, B. Shen, F. Orlandi, H. C. Walker, Y. Liu, C. Cao, F. Steglich, H. Q. Yuan, and M. Smidman, Phys. Rev. B 104, L140411 (2021).
[6] Y. J. Zhang, Z. Y. Nie, R. Li, Y. C. Li, D. L. Yang, B. Shen, Y. Chen, F. Du, S. S. Luo, H. Su, R. Shi, S. Y. Wang, M. Nicklas, F. Steglich, M. Smidman, and H. Q. Yuan, Phys. Rev. B 106, 054409 (2022).
[7] J.-C. Xu, H. Su, R. Kumar, S.-S. Luo, Z.-Y. Nie, A. Wang, F. Du, R. Li, M. Smidman, and H.-Q. Yuan, Chinese Phys. Lett. 38 087101 (2021).

Biography

I completed my PhD at the University of Warwick, UK in 2014, and then moved to the Center for Correlated Matter at Zhejiang University in Hangzhou, to work as a postdoc in the group of Huiqiu Yuan. Since 2018 I have worked as a tenure-track professor at the Center for Correlated Matter and School of Physics at Zhejiang University. My research focusses on experimental studies of unconventional superconductors and strongly correlated electron systems, particularly in measurements under extreme conditions, and using microscopic probes such as neutron scattering and muon-spin relaxation.

Division

Condensed Matter

Other information

Tencent Meeting link: https://meeting.tencent.com/dm/MeNQHX9aNeMF  Meeting ID: 323 523 690