Tunneling junctions for sequencing

A method of determining a sequence of a nucleic acid using a sequencing device, the method comprising:

• adding a set of nucleotides to the sequencing device, wherein:
• each nucleotide of the set of nucleotides is attached to a label compound comprising a moiety,
• the sequencing device comprises a tunneling junction, and
• the tunneling junction comprises a first conductor and a second conductor separated by an insulating layer, wherein:
• the thickness of the insulating layer separating the first conductor and the second conductor is greater than the size of each moiety of each nucleotide of the set of nucleotides,
• the first conductor comprises a first ferromagnetic material, and
• the second conductor comprises a second ferromagnetic material;
• elongating a nascent strand using a polymerase attached to the tunneling junction and connected to a template parent strand to be sequenced, wherein the elongating includes the polymerase incorporating a first nucleotide of the set of nucleotides into the nascent strand via hybridization to the template parent strand;
• measuring a value of an electrical characteristic or a magnetic characteristic through the first conductor, a first moiety of a first label compound attached to the first nucleotide, and the second conductor;
• and
• detecting the first nucleotide as being hybridized to the template parent strand using the value of the electrical characteristic or the magnetic characteristic.