Title: Relaxing Kondo-screened Kramers doublets in $\mathrm{CeRhSi}{}_3$

Abstract

$${\mathrm{CeRhSi}}_{3}$$ is a superconductor under pressure coexisting with a weakly antiferromagnetic phase characterized by a Bragg peak at q^→₀ = (~ 0.2,0,0.5) [N. Aso et al., J. Magn. Magn. Mater. 310, 602 (2007)]. The compound is also a heavy-fermion material with a large specific heat coefficient $${\gamma}=110$$ mJ $${\mathrm{mol}}^{{-}1}{\mathrm{K}}^{{-}2}$$ and a high Kondo temperature of $${T}_{K}=50$$ K, indicating $${\mathrm{CeRhSi}}_{3}$$ is in a strongly Kondo screened state. We apply high-resolution neutron spectroscopy to investigate the magnetic fluctuations in the normal phase, at ambient pressures, and at low temperatures. We measure a commensurate dynamic response centered around the Q^→ = (0,0,2) position that gradually evolves to $$H{\sim}0.2$$ with decreasing temperature and/or energy transfers. The response is broadened both in momentum and energy and is not reminiscent of sharp spin wave excitations found in insulating magnets where the electrons are localized. We parametrize the excitation spectrum and temperature dependence using a heuristic model utilizing the random-phase approximation to couple relaxing $${\mathrm{Ce}}^{3+}$$ ground-state Kramers doublets with a Kondo-like dynamic response. With a Ruderman-Kittel-Kasuya-Yosida exchange interaction within the $ab$ plane and an increasing single-site susceptibility, we can qualitatively reproduce the neutron spectroscopic results in $${\mathrm{CeRhSi}}_{3}$$ and, namely, the trade-off between scattering at commensurate and incommensurate positions. We suggest that the antiferromagnetic phase in $${\mathrm{CeRhSi}}_{3}$$ is driven by weakly correlated relaxing localized Kramers doublets and that $${\mathrm{CeRhSi}}_{3}$$ at ambient pressures is on the border between a Rudderman-Kittel-Yosida antiferromagnetic state and a Kondo-screened phase where static magnetism is predominately absent.

Authors:

Pásztorová, J. ^[1]; Howell, A. ^[1]; Songvilay, M. ^[1]; Sarte, P. M. ^[2]; Rodriguez-Rivera, J. A. ^[3]; Arévalo-López, A. M. ^[4]; Schmalzl, K. ^[5]; Schneidewind, A. ^[6]; Dunsiger, S. R. ^[7]; Singh, D. K. ^[8]; Petrovic, C. ^[9]; Hu, R. ^[9]; Stock, C. ^[1]

---

+ Show Author Affiliations

1. Univ. of Edinburgh, Scotland (United Kingdom). School of Physics and Astronomy
2. Univ. of Edinburgh, Scotland (United Kingdom). School of Chemistry
3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). NIST Center for Neutron Research; Univ. of Maryland, College Park, MD (United States). Dept. of Materials Science
4. École nationale supérieure de chimie de Lille (ENSCL) (France)
5. Forschungszentrum Julich, Grenoble (France). Centre for Neutron Science
6. Research Neutron Source Heinz Maier-Leibnitz (FRM-II), Garching (Germany); TU Dresden (Germany). Inst. of Solid State Physics
7. Technical Univ. of Munich, Garching (Germany). Physics Dept.; TRIUMF, Vancouver, BC (Canada). Centre for Molecular and Materials Science
8. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
9. Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics

Publication Date:

Mon Mar 25 00:00:00 EDT 2019

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Edinburgh, Scotland (United Kingdom)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); Engineering and Physical Sciences Research Council (EPSRC); Carnegie Trust for the Universities of Scotland; Science and Technology Facilities Council (STFC) (United Kingdom)

OSTI Identifier:

1514383

Alternate Identifier(s):

OSTI ID: 1503380

Report Number(s):

BNL-211641-2019-JAAM
Journal ID: ISSN 2469-9950

Grant/Contract Number:  

SC0012704; DMR-1508249

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 99; Journal Issue: 12; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; RKKY interaction; spin dynamics; antiferromagnets; heavy-fermion systems; low-temperature superconductors; noncollinear magnets