Specific Heat of Mg{sup 11}B{sub 2} : Evidence for a Second Energy Gap

Journal Article · Mon Jul 23 00:00:00 EDT 2001 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.87.047001· OSTI ID:40277206

Bouquet, F; Fisher, R A; Phillips, N E; Hinks, D G; Jorgensen, J D

Measurements of the specific heat of Mg{sup 11}B {sub 2} from 1 to 50K, in magnetic fields to 9T, give the Debye temperature, {Theta}=1050 K , the coefficient of the normal-state electron contribution, {gamma}{sub n}=2.6 mJ mol{sup -1} K{sup -2} , and a discontinuity in the zero-field specific heat of 133 mJmol {sup -1} K{sup -1} at T{sub c}=38.7 K . The estimated value of the electron-phonon coupling parameter, {lambda}=0.62 , could account for the observed T{sub c} only if the important phonon frequencies are unusually high relative to {Theta} . At low T , there is a strongly field-dependent feature that suggests the existence of a second energy gap, about 4 times smaller than the major gap.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: (US)
• DOE Contract Number: AC03-76SF00098; W-31-109-ENG-38
• OSTI ID: 40277206
• Journal Information: Physical Review Letters, Vol. 87, Issue 4; Other Information: DOI: 10.1103/PhysRevLett.87.047001; Othernumber: PRLTAO000087000004047001000001; 026130PRL; PBD: 23 Jul 2001; ISSN 0031-9007
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DEBYE TEMPERATURE
ELECTRON-PHONON COUPLING
ELECTRONS
ENERGY GAP
MAGNETIC FIELDS
PHONONS
SPECIFIC HEAT