Microwave Control of the Tin-Vacancy Spin Qubit in Diamond with a Superconducting Waveguide
Ioannis Karapatzakis, Jeremias Resch, Marcel Schrodin, Philipp Fuchs, Michael Kieschnick, Julia Heupel, Luis Kussi, C. Sürgers, Cyril Popov, Jan Meijer, Christoph Becher, Wolfgang Wernsdorfer, David Hunger
Abstract
Group-IV color centers in diamond are promising candidates for quantum networks due to their dominant zero-phonon line and symmetry-protected optical transitions that connect to coherent spin levels. The negatively charged tin-vacancy (SnV) center possesses long electron spin lifetimes due to its large spin-orbit splitting. However, the magnetic dipole transitions required for microwave spin control are suppressed, and strain is necessary to enable these transitions. Recent work has shown spin control of strained emitters using microwave lines that suffer from Ohmic losses, restricting coherence through heating. We utilize a superconducting coplanar waveguide to measure SnV centers subjected to strain, observing substantial improvement. A detailed analysis of the SnV center electron spin Hamiltonian based on the angle-dependent splitting of the ground and excited states is performed. We demonstrate coherent spin manipulation and obtain a Hahn echo coherence time of up to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:msub> <a:mrow> <a:mi>T</a:mi> </a:mrow> <a:mn>2</a:mn> </a:msub> <a:mo>=</a:mo> <a:mn>430</a:mn> <a:mtext> </a:mtext> <a:mtext> </a:mtext> <a:mi mathvariant="normal">μ</a:mi> <a:mi mathvariant="normal">s</a:mi> </a:mrow> </a:math> . With dynamical decoupling, we can prolong coherence to <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:msub> <e:mrow> <e:mi>T</e:mi> </e:mrow> <e:mn>2</e:mn> </e:msub> <e:mo>=</e:mo> <e:mn>10</e:mn> <e:mtext> </e:mtext> <e:mtext> </e:mtext> <e:mi>ms</e:mi> </e:mrow> </e:math> , about a sixfold improvement compared to earlier works. We also observe a nearby coupling <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mmultiscripts> <g:mi mathvariant="normal">C</g:mi> <g:mprescripts/> <g:none/> <g:mrow> <g:mn>13</g:mn> </g:mrow> </g:mmultiscripts> </g:math> spin, which may serve as a quantum memory, thus substantiating the potential of SnV centers in diamond and demonstrates the benefit of superconducting microwave structures. Published by the American Physical Society 2024