Odd-frequency pairing的奇数频率配对.ppt

* * * * * * * * * * * * * * * * * * * * * * DN ＋ ー Even frequency spin triplet odd parity (ETO) pair potential DN ＋ ー (no proximity no MARS) Px-wave case Py-wave case Symmetry of the pair potential Induced pair amplitude in DN (1) Even frequency spin singlet even parity (ESE) Even frequency spin triplet odd parity (ETO) Odd frequency spin triplet even parity (OTE) Odd frequency spin singlet odd parity (OSO) (2) (3) (4) ESE OTE OTE ESE Summary of Proximity effect (diffusive normal metal) How to detect triplet superconductor MARS (Mid gap Andreev resonance state) can penetrate into DN by proximity effect only for triplet superconductor junctions LDOS in DN has a zero energy peak Diffusive normal Metal (DN) STS Triplet superconductor MARS Diffusive normal Metal (DN) STS Singlet superconductor MARS LDOS in DN does not have a zero energy peak ZEP No ZEP How to detect odd-frequency paring amplitude: measuring electrical conductivity 　　　　　　　　　　　　　　　　 Asano, Tanaka, Golubov, Kashiwaya, PRL 99, 067005 (2007) Sr2RuO4　 　 Ａｕ:I+ Ａｕ:V+ Ａｕ:I- Ａｕ:V- Kashiwaya, Maeno 2007 Zero energy peak No Zero energy peak OTE proximity ESE proximity (conventional) OTE (Odd-frequency spin-triplet even-parity) ESE (Even-frequency spin-singlet even-parity) Contents （１）What is odd-frequency pairing （２）Ballistic normal metal junctions （3）Diffusive normal metal junctions （4）Ferromagnet/Superconductor junctions _ Odd frequency spin-triplet s-wave pair Superconductor Ferromagnet Bergeret, Efetov, Volkov, (2001) Eschrig, Buzdin, Kadigrobov,Fominov, Radovic Generation of the odd-frequency pair amplitude in ferromagnet Odd-frequency pair amplitude (not pair potential) is generated in ferromagnet junctions spin-singlet s-wave pair + triplet Josephson effect in SF multilayered system with noncollinear ferromagnets and thin superconductors Spin triplet Cooper pairs in SF systems Josephson current in S/HM/S Half metal : CrO2 Keizer et.al., Nature (2006) Eschrig et.