# Space Charge Effect and Resistance Switching in Doped Monocrystalline Silicones
## 3 Results
Although the influence of a magnetic field on \(N_{D}{}^{+}\) and \(N_{t}\) has not been discussed theoretically [1; 2; 3; 4; 5], from an experimental point, by Equations (1) and (2), \(N_{D}{}^{+}\) and \(N_{t}\) can be estimated from the two critical voltages. Figure 5c shows that both \(N_{D}{}^{+}\) and \(N_{t}\) monotonically increase under magnetic field; meanwhile, \(N_{t}\) is always larger than \(N_{D}{}^{+}\) in any given magnetic field. We propose that the enhancement of \(N_{D}{}^{+}\) is caused by the Zeeman effect on the shallow dopants with half-filled \(p\) states (\(3s^{2}3p^{3}\)) due to the level splitting under a magnetic field. On the other hand, a magnetic field prolongs the relaxation time of carriers combining into neighboring localized states, resulting in the enhancement of \(N_{t}\) under a magnetic field. In accordance, the SCE-RS loop can be modulated by a magnetic field. In Figure 6, red, green, and blue data are SCE-RS loops measured in an 8 mm n-doped Si sample 1126-1# under 0, 5, and 10 kG magnetic field at room temperature. With the increase in magnetic field, the SCE-RS loop is suppressed and the resistance enhances. The magnetic field suppression is negligible in the Ohmic regime, which is consistent with the observation in Figure 5. Evidently, magnetic-dependent SCE-RS loops are the hybrid effect of the modulation by both an electric and magnetic field on SCE. This is clearly different from magnetic field modulation on the RS effect reported in magnetic/semiconductor hybrid devices [20; 24]. In comparison to the memristors, SEC-RS originates from the nonlinear carrier transport and is therefore more susceptible to magnetic fields. In recent years, a significant volume of research has focused on non-volatile memory components in polycrystalline or amorphous materials which underlie the voltage-dependent ionic re-arrangement in nanometer-scale oxide devices. In a single crystal, ionic migration is absent. SCE and the resultant SCE-RS merely originate from the fast dynamics of carriers in a space charge regime modulated by dopants under an external electric field. There is no doubt that a non-volatile memory cell in polycrystalline or amorphous materials is crucial for recording/extracting information. However, the high-field nonlinearity, as well as the volatile RS loops, may provide a way to understand the fast dynamics of carriers in crystals. The present work reports some preliminary experimental observations. It is also expected that the irreversible carrier's dynamics and its related experimental characteristics could receive more attention. In addition, if a memristor is assumed as an analogy for memorization in artificial intelligence, an SCE-RS device could represent a stimuli-response-forgetting process. Both the persistence (remembering) and transience (forgetting) of memory are important to a neural analog circuit. [25] Will people expect to switch these two types of processes in the same cell via feedback signals in the near future? In this sense, SCE-RS may have a potential to extend the functionality of RS devices in neural circuits, especially for all silicon-based devices. Figure 5: Magnetic field dependence of two critical voltages. (**a**) I–V curves of device 0129-1\(\#\) with \(L\) = 2 mm under different magnetic fields measured at room temperature. Red and purple dash lines represent laws of Ohmic and MG, respectively. Insert, magnetic field applied perpendicularly to the sample surface and the current. (**b**) Magnetic field dependence of \(V_{\rm L}\) and \(V_{\rm U}\). (**c**) Magnetic field dependence of \(N_{D}{{}^{+}}\) and \(N_{t}\). In (**b**,**c**), solid lines are the linear fitting guided by eyes to illustrate the magnetic field dependence of those parameters experimentally. **Author Contributions:** [PERSON] fabricated and measured the samples and analyzed the data. [PERSON] supervised the project. [PERSON] and [PERSON] wrote the manuscript. [PERSON] helped to check the details of manuscript independently.