CeSb2 has the immense advantage that clean single crystals are fairly straightforward to grow. It is well-known and - at ambient pressure - has been studied in great detail. However, we found that it undergoes a Dr. Jekyll - Mr. Hyde structural transformation under moderate applied pressure, and in its high pressure structure displays entirely new properties. In a paper now published in Phys. Rev. Lett., a team of QM PhD students Oliver Squire, Stephen Hodgson, Christian de Podesta, and Theo Weinberger, with former QM MPhil student Vitaly Fedoseev, postdoc Jiasheng Chen and high pressure virtuoso Patricia Alireza report that the high pressure structure of CeSb2 hosts a new unconventional superconducting state.
Superconductivity in CeSb2 occurs at a pressure at which a magnetically ordered state is just suppressed, a so-called quantum critical point. It is surprisingly robust against applied magnetic field, prompting renewed theoretical efforts in understanding Pauli paramagnetic limiting in strongly correlated systems, and it forms out of an anomalous normal state with an extremely steep, linear temperature dependence of the resistivity.