Integration of on-chip field-effect transistor switches with dopantless Si/SiGe quantum dots for high-throughput testing

D. R. Ward, D. E. Savage, M. G. Lagally, S. N. Coppersmith, and M. A. Eriksson

Measuring multiple quantum devices on a single chip increases characterization throughput and enables testing of device repeatability, process yield, and systematic variations in device design. The authors present a method that uses on-chip field-effect transistor switches to enable multiplexed cryogenic measurements of double quantum dot Si/SiGe devices.

Appl. Phys. Lett. 102, 213107 (2013) | HTML | PDF

Pyroelectric electron emission from nanometer-thick films of PbZr_xTi_1−xO₃

Patrick C. Fletcher, Vengadesh Kumara R. Mangalam, Lane W. Martin, and William P. King

The authors report pyroelectric emission from PbZr_xTi_1−xO₃ (PZT) thin films on nanometer-sharp tips. The epitaxial PZT films are 30 nm thick and grown directly on single-crystal silicon tips. Pyroelectric emission occurs for heating rates of ≥50 °C/min in a 20 V/μm external field. The emission current is a maximum of 240 nA when the heating rate is 100 °C/min and the electric field strength is ≥6.7 V/μm.

Appl. Phys. Lett. 102, 192908 (2013) | HTML | PDF

Spin torque transistor revisited

Takahiro Chiba, Gerrit E. W. Bauer, and Saburo Takahashi

The authors theoretically study the operation of a 4-terminal device consisting of two lateral thin-film spin valves that are coupled by a magnetic insulator such as yttrium iron garnet via the spin transfer torque. By magnetoelectronic circuit theory they calculate the current voltage characteristics and find negative differential resistance and differential gain in a large region of parameter space.

Appl. Phys. Lett. 102, 192412 (2013) | HTML | PDF

Solitonic Dirac fermion wave guide networks on topological insulator surfaces

René Hammer, Christian Ertler, and Walter Pötz

Magnetic texturing on the surface of a topological insulator allows the design of wave guide networks and beam splitters for domain-wall Dirac fermions. Guided by simple analytic arguments, we model a Dirac domain-wall fermion interferometer consisting of two parallel pathways imprinted by solitonic ferromagnetic texturing.

Appl. Phys. Lett. 102, 193514 (2013) | HTML | PDF

How reliable are Hanle measurements in metals in a three-terminal geometry?

Oihana Txoperena, Marco Gobbi, Amilcar Bedoya-Pinto, Federico Golmar, Xiangnan Sun, Luis E. Hueso, and Fèlix Casanova

The authors show that Hanle measurements in three-terminal devices using aluminum and gold lead to Hanle- and inverted Hanle-like features which are not compatible with spin accumulation in these metals. The measured signals scale with the interface resistance of the tunnel barrier of the devices, suggesting that the origin of these anomalous signals arises from the tunnel barrier itself.

Appl. Phys. Lett. 102, 192406 (2013) | HTML | PDF