Embodiments of the present invention provide a memristor having a first electrode, a second electrode and a memristive layer arranged between the first electrode and the second electrode. Thereby, the memristor is adapted to obtain an asymmetrical current density distribution in the memristive layer.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. An artificial tripartite synapse, comprising: a memristor, comprising a first electrode, a second electrode and a memristive layer arranged between the first electrode and the second electrode, wherein the memristor is adapted to obtain an asymmetrical current density distribution in the memristive layer; and a field effect transistor; wherein the memristor is connected to a gate of the field effect transistor; wherein the memristive layer comprises an asymmetrical doping density distribution or an asymmetrical trap density distribution in order to obtain the asymmetrical current density distribution in the memristive layer; and wherein the current density varies along an equipotential line within the memristive layer or wherein the current density within the memristive layer is asymmetrical along a current path from the first electrode to the second electrode. 2. The artificial tripartite synapse according to claim 1, wherein a conductive cross-section of the memristive layer varies along a current path from the first electrode to the second electrode. 3. The artificial tripartite synapse according to claim 1, wherein the memristor comprises an asymmetry with respect to an unchangeable structural feature of the memristor, to obtain the asymmetrical current density distribution in the memristive layer. 4. The artificial tripartite synapse according to claim 3, wherein the unchangeable structural feature is a geometrical feature. 5. The artificial tripartite synapse according to claim 3, wherein the unchangeable structural feature is a material feature of the memristor which is unaffected by a state of the memristor. 6. The artificial tripartite synapse according to claim 1, wherein an area of the first electrode is at least by a factor of 1.5 greater than an area of the second electrode, in order to obtain the asymmetrical current density distribution in the memristive layer. 7. The artificial tripartite synapse according to claim 1, wherein an area of the memristive layer contacting the first electrode is at least by a factor of 1.5 greater than an area of the memristive layer contacting the second electrode, in order to obtain the asymmetrical current density distribution in the memristive layer. 8. The artificial tripartite synapse according to claim 1, wherein the memristive layer comprises TiO2. 9. The artificial tripartite synapse according to claim 1, wherein the first electrode and/or the second electrode comprises Ti. 10. A neural network comprising an artificial tripartite synapse according to claim 1. 11. The neural network according to claim 10, further comprising: a first neuron; a second neuron; wherein the artificial tripartite synapse is connected in series between the first neuron and the second neuron.