Direct Entropy Measurement in a Mesoscopic Quantum System

ORAL

Abstract

Entropy measurements, typically derived from bulk properties (e.g. heat capacity), are difficult to access in mesoscopic samples. Taking advantage of a well-known Maxwell relation, we build a mesoscopic device in which it is possible to measure the entropy of quantum states down to the single electron level. To demonstate the efficacy of this method, we apply it to the first few-electron spin states in a gate-defined GaAs quantum dot. The entropy of a single spin (kB ln 2) can be determined within 5% accuracy, as can the entropy at the singlet-triplet crossing for two electrons in a large magnetic field. Looking forward, this measurement approach will be applied to systems with less trivial ground states, such as one or two-channel Kondo systems.

–

Presenters

  • Nikolaus George Hartman

    Univ of British Columbia

Authors

  • Nikolaus George Hartman

    Univ of British Columbia

  • Christian Olsen

    Physics and Astronomy, University of British Columbia, Univ of British Columbia

  • Saeed Fallahi

    Purdue University, Physics, Purdue University, Purdue Univ, Department of Physics and Astronomy, and School of Materials Engineering, and School of Electrical and Computer Engineering, Purdue University

  • Michael Manfra

    Department of Physics and Astronomy and Station Q Purdue, Purdue University, Department of Physics and Astronomy and Microsoft Station Q Purdue, Purdue University, Purdue University, Physics, Purdue University, Purdue University, Station Q Purdue, Purdue Univ, Department of Physics and Astronomy, and School of Materials Engineering, and School of Electrical and Computer Engineering, Purdue University, Physics and Astronomy, Purdue University, Dept. of Physics and Astronomy, Purdue Univ

  • Joshua Folk

    Physics and Astronomy, University of British Columbia, Univ of British Columbia