1 / 21

The Ideal Electron Gas Thermometer

The Ideal Electron Gas Thermometer. Lafe Spietz, K.W. Lehnert, I. Siddiqi, R.J. Schoelkopf Department of Applied Physics, Yale University Thanks to: Michel Devoret and Daniel E. Prober. Introduction.

kali
Télécharger la présentation

The Ideal Electron Gas Thermometer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Ideal Electron Gas Thermometer Lafe Spietz, K.W. Lehnert, I. Siddiqi, R.J. Schoelkopf Department of Applied Physics, Yale University Thanks to: Michel Devoret and Daniel E. Prober

  2. Introduction • Johnson-Schottky transition of the noise in tunnel junctions • Relates T and V using only e and kB •  primary thermometer • Demonstrate operation from T=0.26 K to 300K

  3. Fundamental Noise Sources Thermal(Johnson) Noise • Frequency-independent • Temperature-dependent • Used for thermometry Shot(Schottky) Noise • Frequency-independent • Temperature independent

  4. Conduction in Tunnel Junctions M I M Difference gives current: Fermi functions Assume: Tunneling amplitudes and D.O.S. independent of energy Fermi distribution of electrons Conductance (G) is constant

  5. Thermal-Shot Noise of a Tunnel Junction* Sum gives noise: *D. Rogovin and D.J. Scalpino, Ann Phys. 86,1 (1974)

  6. Thermal-Shot Noise of a Tunnel Junction 2eGV=2eI Shot Noise Johnson-Schottky Transition Region eV~kBT 4kBT Thermal Noise R

  7. Johnson-Schottky Transition: Direct relationship between T and V

  8. Tunnel Junction(AFM image) R=33 W Area=10 mm2 Al-Al2O3-Al Junction V+ I+ I- V-

  9. Experimental Setup:RF + DCMeasurement

  10. Experimental Setup: Pumped He Cryostat Noise power vs. bias voltage: High bandwidth: hence fast For t= 1 second,

  11. Self-Calibration Technique for Thermometry P = Gain*B( SIAmp+SI(V,T) )

  12. Noise Versus Voltage T=4.372 K Tnoise=5.128 K, Gain=29.57 mV/K

  13. Universal Functional Form: Agreement over three decades In temperature

  14. Comparison With Secondary Thermometers

  15. Temperature Measurements Over Time

  16. Merits Vs. Systematics Merits • Systematics • I-V curve nonlinearities • Amplifier and diode nonlinearities • Frequency dependence* • Self-heating • Fast and self-calibrating • Primary • Wide T range (mK to room temperature) • No B-dependence • Compact electronic sensor • Possibility to relate T to frequency!* *R. J. Schoelkopf et al., Phys Rev. Lett. 80, 2437 (1998)

  17. Summary • Ideal Electron Gas Thermometer based on Johnson-Schottky transition of noise in a tunnel junction (thermal-shot noise.) • Fast, accurate, primary thermometer • Works over a wide temperature range • Relates T to V using only e and kb applications for metrology

  18. Diode Nonlinearity Vdiode = GP + bG2P2 b= -3.1 V-1 1mV => 3x10-3 fractional error

  19. Conductance R=31.22Ohms

  20. More Conductance

  21. 2 3 1 4

More Related