  We have developed an approach to control the carrier density in various
material under high pressure by the combination of an electric double layer
transistor (EDLT) with a diamond anvil cell (DAC). In this study, this EDLT-DAC
was applied to a Bi thin film, and here we report the field-effect under high
pressure in the material. Our EDLT-DAC is a promising device for exploring
unknown physical phenomena such as high transition-temperature
superconductivity (HTS).
