In an electron system coupled with anharmonic phonons, i.e., rattling, inverse isotope effect on the Kondo temperature TK is found to occur by the numerical evaluation of the Sommerfeld constant γ of the Anderson-Holstein model. For the anharmonic potential of an oscillator with mass M in which large γ has been found to be almost independent of an applied magnetic field, γ is significantly suppressed when M is increased, i.e., TK is enhanced due to the relation of γ∼ TK-1 in the Kondo problem, leading to the inverse isotope effect on TK. Since this phenomenon does not occur for harmonic phonons, it can be a key experiment to prove the relevance of rattling to magnetically robust heavy electron state.
Journal of the Physical Society of Japan
- Pub Date:
- July 2009
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Materials Science
- 4 pages, 3 figures. To appear in J. Phys. Soc. Jpn