Florida State University의 Luis Balicas 교수님을 초청하여 아래와 같이 세미나를 개최합니다.

학과 구성원 여러분의 많은 참석을 부탁 드립니다. 

         아             래  

     1. 일시: 2015년 4월 7일(화) 오전 11시

     2. 장소: 삼성학술정보관 7층 Creative Learning Room

     3. 초청연사: Prof. Luis Balicas  (Florida State University)

     4. 제목: Recent developments in superconductivity at high magnetic fields

     5. Abstract: Here, I will discuss high magnetic field results [1] in the superconducting state of URu2Si2, which was claimed to be a candidate for a chiral d-wave superconductor having a kz(kx+iky) pairing symmetry. Through low temperature torque magnetometry, we show that the diamagnetic signal expected from vortex pinning, crosses over to an enhanced paramagnetic-like response for fields just below Hc2 when the field approaches the ab-plane. We argue that this anomalous response can only be attributed to supercurrents circulating in the opposite sense with respect to the screening supercurrents, and therefore it might correspond to possible evidence for the sought after chiral state. Remarkably, we have seen a similar response also in LiFeAs [2, 3]. For both compounds, only the highest quality single crystals (i.e. lowest residual resistivity) are found to display such an effect, suggesting superconducting states that are very sensitive to disorder.  Finally, we will briefly discuss the properties of new Pd based chalcogenide superconductors displaying extremely high upper critical fields [4, 5].

References
[1] G. Li et al., Phys. Rev. B 88, 134517 (2013).
[2] G. Li et al., Phys. Rev. B 87, 024512 (2013).
[3] B. Zeng et al., Phys. Rev. B 88, 144518 (2013).
[4] Q. Zhang et al., Sci. Rep. 3, 1446 (2013).
[5] Q.R. Zhang et al., Phys. Rev. B 88, 024508 (2013).