2020/07/31 by Mohammed Ali Aamir, John N. Moore, Xiaobo Lu +5 · 33 citations
Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Calorimetry #Condensed matter physics #Graphene #Graphene research and applications #Heat capacity #Materials science #Nanotechnology #Optoelectronics #Physics #Quantum mechanics #Relaxation (psychology) #Thermal #Thermal properties of materials #Thermodynamics #Thermometer #cond-mat.mes-hall #van der Waals force
paper · pdf · doi:10.1021/acs.nanolett.1c01553
published in Nano Letters 21(12), 5330-5337 (American Chemical Society)
arxiv created 2020/12/24 · openalex publication_date 2021/06/08 · arxiv updated 2021/07/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Heat capacity is an invaluable quantity in condensed matter physics and yet has been completely inaccessible in two-dimensional (2D) van der Waals (vdW) materials, owing to their ultrafast thermal relaxation times and the lack of suitable nanoscale thermometers. Here, we demonstrate a novel thermal relaxation calorimetry scheme that allows the first measurements of the electronic heat capacity of graphene. It is enabled by combining a radio frequency Johnson noise thermometer, which can measure the electronic temperature with a sensitivity of ∼20 mK/Hz 1/2, and a photomixed optical heater that modulates T e with a frequency of up to Ω = 0.2 THz. This allows record sensitive measurements of the electronic heat capacity C e < 10 –19 J/K and the fastest measurement of electronic thermal relaxation time τ e < 10 –12 s yet achieved by a calorimeter. These features advance heat capacity metrology into the realm of nanoscale and low-dimensional systems and provide an avenue for the investigation of their thermodynamic quantities.