Hierarchy of the density-wave states and superconductivity in the organic conductor α-(BEDT-TTF)2KHg(SCN)4

The layered organic conductor α-(BEDT-TTF)2KHg(SCN)4 exhibits a phase transition into the charge-density-wave (CDW) state at an unusually low temperature. This leads to a very high sensitivity of the ground state to magnetic field and pressure. We present a number of novel field-induced CDW states originating from the superposition of the strong paramagnetic and quantized orbital effects of the magnetic field. At temperatures below 0.3 K the CDW phase coexists with a superconducting phase. Surprisingly, the CDW formation is found to remarkably increase the superconducting onset temperature.