Nonmagnetic fractional conductance in high mobility InAs quantum point contacts

In this paper, we report the magnetoelectronic properties of high mobility InAs quantum point contacts grown on InP substrates. The InAs quantum well is embedded between <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>In</a:mi><a:mrow><a:mn>0.72</a:mn></a:mrow></a:msub><a:msub><a:mi>Ga</a:mi><a:mrow><a:mn>0.28</a:mn></a:mrow></a:msub><a:mi>As</a:mi></a:mrow></a:math> cladding layers and <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:msub><b:mi>In</b:mi><b:mrow><b:mn>0.81</b:mn></b:mrow></b:msub><b:msub><b:mi>Al</b:mi><b:mrow><b:mn>0.19</b:mn></b:mrow></b:msub><b:mi>As</b:mi></b:mrow></b:math> barrier layers, and is populated via self-accumulation. The one-dimensional (1D) conductance reaches a maximum value of 17 plateaus, quantized in units of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>2</c:mn><c:msup><c:mrow><c:mi>e</c:mi></c:mrow><c:mn>2</c:mn></c:msup><c:mo>/</c:mo><c:mi>h</c:mi></c:mrow></c:math>, where <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mi>e</d:mi></d:math> is the fundamental unit of charge and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mi>h</e:mi></e:math> is Planck's constant. The in-plane effective <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mi>g</f:mi></f:math> factor was estimated to be <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mo>−</g:mo><g:mn>10.9</g:mn><g:mo>±</g:mo><g:mn>1.5</g:mn></g:mrow></g:math> for subband <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:mrow><h:mi>N</h:mi><h:mo>=</h:mo><h:mn>1</h:mn></h:mrow></h:math> and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mrow><i:mo>−</i:mo><i:mn>10.8</i:mn><i:mo>±</i:mo><i:mn>1.6</i:mn></i:mrow></i:math> for subband <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:mrow><j:mi>N</j:mi><j:mo>=</j:mo><j:mn>2</j:mn></j:mrow></j:math>. Furthermore, a study of the nonmagnetic fractional conductance states at 0.2 (<k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mrow><k:msup><k:mi>e</k:mi><k:mn>2</k:mn></k:msup><k:mo>/</k:mo><k:mi>h</k:mi></k:mrow></k:math>) and 0.1 (<l:math xmlns:l="http://www.w3.org/1998/Math/MathML"><l:mrow><l:msup><l:mi>e</l:mi><l:mn>2</l:mn></l:msup><l:mo>/</l:mo><l:mi>h</l:mi></l:mrow></l:math>) is provided. While their origin remains under discussion, evidence suggests that they arise from strong electron-electron interactions and momentum-conserving backscattering between electrons in two distinct channels within the 1D region. This phenomenon may also be interpreted as an entanglement between the two channel directions facilitated by momentum-conserving backscattering.