Low Temperature Two Fluid State in SmB6

2025/11/10 by Ghosh, Sayantan, Paul, Sugata, Chattoraj, Tamoghna +3
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)

paper · doi:10.48550/arxiv.2511.07000

Abstract

Comprehensive study using DC transport, specific heat, magnetization, and two-coil mutual inductance measurements unveils an understanding of three temperature regimes in SmB₆: (i) T ≥ T^* (∼66K), (ii) T_g (∼40 K) ≤ T < T^*, and (iii) T < T_g. Onset of Kondo breakdown below T^* releases disorder-driven magnetic fluctuations, which splits the bulk (∼116K) and surface Kondo temperature (T_k^s ≈ 7 K). Below T_g, as magnetic fluctuations subside, surface Kondo screening revives, stabilizing the topological surface state and generating an in-gap feature (∼2.2 meV) across which Dirac-like carriers are excited. Nyquist impedance analysis reveals a crossover from purely capacitive to capacitive-inductive behavior, signalling a disorder-driven two-fluid phase of heavy quasiparticles and light, high-mobility carriers below T_g. We identify a characteristic length scale, L_ν0(T), associated with the high-mobility phase, exhibiting an almost divergent trend below T_k^s. These findings underscore the complex nature of the surface conducting state in SmB₆.

Related

• Exploration of strongly correlated states in SmB6 through a comparison of its two-coil pick-up response to that of Bi2Se3
• Magnetoresistance evidence on surface state and field-dependent bulk gap in Kondo insulator SmB6
• Robust local and non-local transport in the Topological Kondo Insulator SmB₆ in the presence of high magnetic field
• Screened moments in a Kondo insulator
• Surface electronic structure of a topological Kondo insulator candidate SmB6: insights from high-resolution ARPES