Fabrication of pico-Calorimeter
Fan-Yun Chiu1,2,3*, Min-nan Ou3, Chia-Seng Chang1,2,3, Yang-Yuan Chen3
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan University, Taipei, Taiwan
3Institute of Physics, Academia Sinica, Taipei, Taiwan
* presenting author:Fan-Yun Chiu, email:fychiu@gate.sinica.edu.tw
In solid state physics, thermodynamic measurements give a variety of information on fundamental properties and provide direct insight into, e. g., phonon and electron density of states and phase transitions. In this work, the so called thermal relaxation technique is employed for the design of a pico-calorimetry, which is designed for thin crystal sample. The sample holder is made with dimensions of 70 μm × 70 μm × 300 nm on a Si3N4/Si substrate by means of photolithography patterning. A Ni-Cr bridge and a film of RuO2 is deposited to the holder as the heater and thermometer, respectively. The holder is suspended by six free-standing Au-Cu wires which are tuned to minimize the thermal conductance for increasing the time resolution in etching process. By adjusting the thermal conductance of the wires, the relaxation time constant is controlled as low as 0.1 seconds, corresponding to the heat capacity resolution of ~ 32 pJ/K. Using an optical microscopy, a sub-micrometer resolution mechanical stage is developed to manipulate the mesoscopic sample which is picked up and positioned on the pico-calorimetry with a tungsten tip. The pico-calorimetry is employed to study the superconductivity of layered material for finding Majorana fermions. The thermodynamics properties may provide advanced information for the study of unconventional superconductivity with gap nodes.

Keywords: calorimetry, pico-calorimetry