A new Regime of Pauli-Spin Blockade

• Main Authors: Perron, Justin K, StewartJr, M. D, Zimmerman, Neil M
• Format: Journal Article
• Language: English
• Published: 27-07-2015
• Subjects: Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.1507.07515

Pauli-spin blockade (PSB) is a transport phenomenon in double quantum dots
that allows for a type of spin to charge conversion often used to probe
fundamental physics such as spin relaxation and singlet-triplet coupling. In
this paper we theoretically explore Pauli-spin blockade as a function of
magnetic field B applied parallel to the substrate. In the well-studied low
magnetic field regime, where PSB occurs in the forward $(1,1)\rightarrow(0,2)$
tunneling direction, we highlight some aspects of PSB that are not discussed in
detail in existing literature, including the change in size of both bias
triangles measured in the forward and reverse biasing directions as a function
of B. At higher fields we predict a crossover to \reverse PSB" in which current
is blockaded in the reverse direction due to the occupation of a spin singlet
as opposed to the traditional triplet blockade that occurs at low fields. The
onset of reverse PSB coincides with the development of a tail like feature in
the measured bias triangles and occurs when the Zeeman energy of the polarized
triplet equals the exchange energy in the (0,2) charge configuration. In Si
quantum dots these fields are experimentally accessible; thus, this work
suggests a way to probe singlet to triplet relaxation mechanisms in quantum
dots when both electrons occupy the same quantum dot.