Quenching of orbital momentum by crystalline fields in a multichannel Kondo impurity
- Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)
- Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of)
We consider an impurity of spin {ital S} interacting via an isotropic spin exchange with conduction electrons of spin 1/2. The conduction electrons can be in {ital n} different orbital channels. We assume that crystalline fields split the orbital degrees of freedom into two multiplets, the one with lower energy consisting of {ital n}{sup *} orbitals and the one of higher energy of {ital n}{minus}{ital n}{sup *} orbitals. The exchange coupling is the same for all channels. We derive the thermodynamic Bethe ansatz equations for this model and discuss the ground-state properties of the impurity as a function of the spin {ital S} and the magnetic field. The solution of the ground-state Bethe ansatz equations is obtained numerically. Three situations have to be distinguished when the magnetic field is small compared to the Kondo temperature: (i) If {ital S}={ital n}/2 or {ital S}={ital n}{sup *}/2 the conduction electrons exactly compensate the impurity spin into a singlet ground state, (ii) if {ital S}{gt}{ital n}/2 the impurity is undercompensated, i.e., only partially compensated leaving an effective spin {ital S}{minus}{ital n}/2 at low temperatures, and (iii) in all other cases the impurity spin is overcompensated giving rise to critical behavior. The quenching of the orbits by the crystalline field dramatically affects the cases {ital S}{lt}{ital n}/2, i.e., the critical behavior of the overcompensated multichannel Kondo impurity and the singlet ground state with {ital S}={ital n}{sup *}/2.
- OSTI ID:
- 115825
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 9 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
Similar Records
One-dimensional heavy fermion lattice model
Finite-size effects in a metallic multichannel ring with Kondo impurity: Persistent currents and magnetoresistance